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Significantly simplified how the plugin operates based on a better understanding of WP dependencies.
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Dominic P
  • 705
  • 3
  • 10
  • 24
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order forProcess the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scriptsdependency firsttree, then footer scripts).
     but don't print anything
        We also have to pull in any additional scripts that were enqueued late ob_start(e.g. in shortcodes)
        via the nested array_merge. So,we append the scripts in the $wp_scripts->queue property
        to the end of the $wp_scripts->in_footer property. These will likely be mostly duplicates,
        but those will be pulled out in the next step.
        */;
        $this->script_queue$script_queue = array_merge( $this->script_queue, array_merge( $wp_scripts->in_footer, $wp_scripts->queue ) >do_items();
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_uniqueob_clean( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue$script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue$script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue$script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        
        We also have to pull in any additional scripts that were enqueued late (e.g. in shortcodes)
        via the nested array_merge. So,we append the scripts in the $wp_scripts->queue property
        to the end of the $wp_scripts->in_footer property. These will likely be mostly duplicates,
        but those will be pulled out in the next step.
        */
        $this->script_queue = array_merge( $this->script_queue, array_merge( $wp_scripts->in_footer, $wp_scripts->queue ) );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
class example {
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

    // Process the scripts dependency tree, but don't print anything
    ob_start();
    $script_queue = $wp_scripts->do_items();
    ob_clean();
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
Fixed another bug that caused some scripts to be missed if they were enqueued late.
Source Link
Dominic P
  • 705
  • 3
  • 10
  • 24
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        
        We also have to pull in any additional scripts that were enqueued late (e.g. in shortcodes)
        via the nested array_merge. So,we append the scripts in the $wp_scripts->queue property
        to the end of the $wp_scripts->in_footer property. These will likely be mostly duplicates,
        but those will be pulled out in the next step.
        */
        $this->script_queue = array_merge( $this->script_queue, array_merge( $wp_scripts->in_footer, $wp_scripts->queue ) );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        */
        $this->script_queue = array_merge( $this->script_queue, $wp_scripts->in_footer );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        
        We also have to pull in any additional scripts that were enqueued late (e.g. in shortcodes)
        via the nested array_merge. So,we append the scripts in the $wp_scripts->queue property
        to the end of the $wp_scripts->in_footer property. These will likely be mostly duplicates,
        but those will be pulled out in the next step.
        */
        $this->script_queue = array_merge( $this->script_queue, array_merge( $wp_scripts->in_footer, $wp_scripts->queue ) );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
Fixed code typo that prevented the CDN fallback functionality from working properly.
Source Link
Dominic P
  • 705
  • 3
  • 10
  • 24
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        */
        $this->script_queue = array_merge( $this->script_queue, $wp_scripts->in_footer );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", completecallback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        */
        $this->script_queue = array_merge( $this->script_queue, $wp_scripts->in_footer );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", complete: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
class example {
    
    /*
    An array to hold the script queue so we can use a js, asynchronous script loader
    instead of a bunch of script tags
    */
    public $script_queue = array();
    
    function __construct() {
    
        /*
        Hook into the script printing functionality and use our own resource loader to load
        scripts in a non-blocking, asynchronous, parallel fancy way
        */
        if( !is_admin() ) {
            
            add_action( 'wp_print_scripts',  array( &$this, 'deploy_script_loader' ) );
        }       
    }   
    
    /*
    If we have any javascripts queued for the page, grab the handles of
    all of the ones to be loaded in the header and dequeue them now. 
    Then, we will check again and reload any that weren't queued
    yet in the footer.
    */
    function deploy_script_loader( ) {
        global $wp_scripts;

        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            // Get the queue in our class property, and dequeue everything
            foreach ( $wp_scripts->queue as $handle ) {

                /*
                Check if this script is supposed to be loaded in the header (group isn't 1).
                If it is, we'll grab it now and dequeue it. We'll save the rest of the dequeuing
                for the footer script or else we'll miss some scripts that are queued after
                this hook is run.
                */
                if ( 1 !== $wp_scripts->registered[$handle]->extra['group'] ) {
            
                    // Grab the handle for later and dequeue the script
                    $this->script_queue[] = $handle;
                    wp_dequeue_script( $handle );
                    
                    /*
                    Just dequeuing a script here isn't enough to prevent it from being
                    printed in the header if another script that we haven't dequeued (ie a footer
                    script) depends on it. So, we need to make sure that all of the
                    scripts we just dequeued will be ok loading in the footer (where they will
                    get dequeued for real before they are printed).
                    */
                    $wp_scripts->registered[$handle]->extra['group'] = 1;
                }
            }
            
            // Add our hook to load everything in the footer
            add_action( 'wp_footer', array( &$this, 'output_script_loader' ) );
        }       
    }

    /*
    Function to be ran in wp_footer to output the js script loader
    html content.
    */
    function output_script_loader() {
        global $wp_scripts;

        // Finish dequeuing all the scripts that are supposed to be loaded in the footer
        if ( !empty( $wp_scripts->queue ) && !is_admin() ) {
            
            foreach ( $wp_scripts->queue as $handle ) {
                
                wp_dequeue_script( $handle );
            }
        }
        
        /*
        Now, we have a array of scripts that were queued for the header ($this->script_queue)
        The proper order for the scripts queued for the footer is found in the in_footer
        property of the global $wp_scripts object. So, we'll need to get a single array to
        hold all of our handles in the proper order (header scripts first, then footer scripts).
        */
        $this->script_queue = array_merge( $this->script_queue, $wp_scripts->in_footer );
        
        /*
        Remove any duplicate values so scripts don't get loaded twice. This can happend because
        scripts that were dequeued in the header may still be listed in the $wp_scripts->in_footer
        array because other footer scripts are dependant on them, so they get requeued. This
        step prevents the double loading.
        */
        $this->script_queue = array_unique( $this->script_queue );
        
        // Add our script loader
        echo '<script type="text/javascript" src="' . plugins_url( '/scripts/yepnope.1.0.2-min.js', __FILE__ ) . '"></script><script type="text/javascript">';
        
        // Loop through the queued scripts and get all of their localization output objects first
        foreach( $this->script_queue as $handle ) {
                
            echo $wp_scripts->registered[$handle]->extra['data'];
        }
                
        echo 'yepnope.errorTimeout = 4000; yepnope([';
        
        $i = 0;
        $count = count( $this->script_queue );
        
        // Loop through the queued scripts again, this time output the script loader syntax
        foreach( $this->script_queue as $handle ) {

            if ( 'jquery' === $handle ) {
                
                $jquery_cdn_url = ( is_ssl() ) ? 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js' : 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
                
                echo ' { load: "'. $jquery_cdn_url .'", callback: function () { if (!window.jQuery) { yepnope("' . $wp_scripts->base_url . $wp_scripts->registered['jquery']->src . '"); } } },';
            } else {
                
                $src = $wp_scripts->registered[$handle]->src;
                
                // Check if this is a relative path or if we have the whole thing
                if( 'http' !== strtolower( substr( $src, 0, 4 ) ) ) {
                    
                    $src = $wp_scripts->base_url . $src;
                } else {
                    
                    $src = ( is_ssl() ) ? 'https' . substr( $src, strpos( $src, ':' ), strlen( $src ) ) : 'http' . substr( $src, strpos( $src, ':' ), strlen( $src ) );
                }
                
                $comma = ( $i == ( $count - 1 ) ) ? '' : ',';
                
                echo '{ load: "' . $src . '" }' . $comma;
            }

            $i++;
        }       
                
        echo ']);</script>';
    }
}

// Instantiate the class
new example;
Source Link
Dominic P
  • 705
  • 3
  • 10
  • 24
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