Link a Theme Script Which Depends on jQuery

JavaScript files included in themes often require another JavaScript file to be loaded in advance to use its functions or variables. Using the $deps parameter, the wp_enqueue_script() and wp_register_script() functions allows you to mark dependencies when registering a new script. This will cause WordPress to automatically link these dependencies to the HTML page before the new script is linked. If the handles of these dependencies are not registered, WordPress will not link the new script. This example requires the jQuery library for the custom_script.js theme script:

/**
 * Enqueue a script with jQuery as a dependency.
 */
function wpdocs_scripts_method() {
	wp_enqueue_script( 'custom-script', get_stylesheet_directory_uri() . '/js/custom_script.js', array( 'jquery' ) );
}
add_action( 'wp_enqueue_scripts', 'wpdocs_scripts_method' );

Link the script.aculo.us Library

The following is an example of basic usage which links the script.aculo.us library already included and registered by WordPress with the scriptaculous handle.

/**
 * Enqueue script.aculo.us.
 *
 * Tha callback is hooked to 'wp_enqueue_script' to ensure the script is only enqueued on the front-end.
 */
function my_scripts_method() {
    wp_enqueue_script( 'scriptaculous' );
}
add_action( 'wp_enqueue_scripts', 'my_scripts_method' );

The above example links the script.aculo.us library only on the front-end. If the library was needed within the administration screens, you could use the admin_enqueue_scripts action hook instead, however, this would enqueue it on all the administration screens, which often leads to plugin/core conflicts, ultimately breaking the WordPress administration screens experience. Instead, you should only link it on the individual screens you need it, see the Link Scripts Only on a Plugin Administration Screen section for an example of that.

Link a Plugin Script That Depends on script.aculo.us

This example is intended to be used within a plugin file to register and link a new plugin script that depends on the script.aculo.us library. See the example above for information about dependencies.

/**
 * Enqueue script with script.aculo.us as a dependency.
 */
function my_scripts_method() {
	wp_enqueue_script( 'newscript', plugins_url( '/js/newscript.js' , __FILE__ ), array( 'scriptaculous' ) );
}
add_action( 'wp_enqueue_scripts', 'my_scripts_method' );