include jquery plugin file not working

Question

My code for include js as follows:

function you_fancy_js(){
    wp_register_script( 'custom-script', plugins_url( '/js/jquery.js', __FILE__ ), array( 'jquery', 'jquery-ui-1.8.18.custom.min', 'jquery.validate.min' ) );  
    wp_enqueue_script( 'custom-script' );
}
add_action('wp_enqueue_scripts','you_fancy_js');
add_action('admin_head','you_fancy_js');

The above code should include a js file. It is not working.

Answer 1

Your uses of wp_register_script and add_action are incorrect. Try the following code:

function you_fancy_js(){
    wp_register_script( 'custom-script', plugins_url( '/js/jquery.js', __FILE__ ), array( 'jquery', 'jquery-ui-core', 'jquery-validate' ) );  
    wp_enqueue_script( 'custom-script' );
}
add_action('wp_enqueue_scripts','you_fancy_js');

This assumes that your custom jQuery functions are in jquery.js and jquery, jquery-ui-core, and jquery-validate are already enqueued. You do not need admin_head. The admin equivalent of wp_enqueue_scripts is admin_enqueue_scripts.

Answer 2

jQuery is already a part of the core package and may very well already have been enqueued by a plugin or by the theme if you are modding a theme rather than writing from scratch. Including it again with a handle other than jQuery is likely to run into problems even if your code worked.

If you are going to enqueue jQuery from a source other than the core it is best to deregister it and then register your source before enqueue.

You should also use the init hook to attach your script function and leave the core jQuery inclusion alone when in the admin.

Finally, there are a number of good reasons to de-register the included jQuery and include the one from the Google AJAX repository.

Try this:

 /**
 * Add jQuery from Google ajax library
 */
function dmm_add_jquery() {
    if (!is_admin()) {
        // comment out the next two lines to load the local copy of jQuery
        wp_deregister_script('jquery');
        wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js', false, '1.3.2');
        wp_enqueue_script('jquery');
    }
}
add_action('init', 'dmm_add_jquery');