How can I load jquery library into my dashboard widget?

Question

I'm attempting to use wp_enqueue_script('jquery') to load the builtin WP jquery library but my jquery functions aren't working when I do this. Only when I hardcode a reference to the script do my functions work...

Example that works... (this is inside my functions.php file, which is adding a dashboard widget)...

/* Dashboard Widget */
if(is_admin())
{
function my_dashboard_widget_function() 
{ 
    $rss = fetch_feed( "http://mysite/my.rss" );
    if ( is_wp_error($rss) ) 
    {
        if ( is_admin() || current_user_can('manage_options') ) 
        {
            echo '<p>';
            printf(__('<strong>RSS Error</strong>: %s'), $rss->get_error_message());
            echo '</p>';
        }
     return;
    }

    if ( !$rss->get_item_quantity() ) 
    {
        echo '<p>This feed is currently offline</p>';
        $rss->__destruct();
        unset($rss);
        return;
    }
echo "<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js'></script>"

echo "<script type='text/javascript'>//some jquery methods here</script>";

Example that does not work...

/* Dashboard Widget */
if(is_admin())
{
function my_dashboard_widget_function() 
{ 
    $rss = fetch_feed( "http://mysite/my.rss" );
    if ( is_wp_error($rss) ) 
    {
        if ( is_admin() || current_user_can('manage_options') ) 
        {
            echo '<p>';
            printf(__('<strong>RSS Error</strong>: %s'), $rss->get_error_message());
            echo '</p>';
        }
     return;
    }

    if ( !$rss->get_item_quantity() ) 
    {
        echo '<p>This feed is currently offline</p>';
        $rss->__destruct();
        unset($rss);
        return;
    }
wp_enqueue_script('jquery');
echo "<script type='text/javascript'>//some jquery methods here</script>";

Answer 1

You need to enqueue your script at certain points. Rather than just placing the wp_enqueue_script call inside your dashboard widget function, you need to place it in a separate function and hook on to the proper action.

So:

function add_jquery_to_my_widget() {
    wp_enqueue_script( 'jquery' );
}
add_action( 'init', 'add_jquery_to_my_widget' );