How to add custom javascript to WordPress Admin?

Question

I want to add some custom jquery code to the Edit Post page, something really simple like showing a div when someone presses Publish.

The only restriction is that I want to achieve this through the use of a plugin, not hacking the admin template files.

I've tried echoing some script tags using some actions but it doesn't seem to be the way.

Answer 1

There is a snippet for Your functions.php file :

function custom_admin_js() {
    $url = get_bloginfo('template_directory') . '/js/wp-admin.js';
    echo '"<script type="text/javascript" src="'. $url . '"></script>"';
}
add_action('admin_footer', 'custom_admin_js');

Works fine on Wordpress 3.2.1.

Answer 2

admin_enqueue_scripts and wp_enqueue_script are the preferred way to add javascript files to the dashboard.

// I'm using an anonymous function for brevity.
add_action( 'admin_enqueue_scripts', function() {
    wp_enqueue_script( 'handle', plugin_dir_url( __FILE__ ) . '/script.js' );
} );

If you want to output the javascript using your PHP function however, wp_add_inline_script doesn't seem to work. Instead, you can use admin_print_scripts to directly echo out the script, including the script tags themselves. Just ensure to set the priority high so that it loads after any required libraries, such as jQuery.

add_action( 'admin_print_scripts', function() {
    // I'm using NOWDOC notation to allow line breaks and unescaped quotation marks.
    echo <<<'EOT'
<script type="text/javascript">
jQuery(function($){
    // Do stuff here.
});
</script>
EOT;
}, PHP_INT_MAX );

Answer 3

Use the admin_enqueue_scripts action and the wp_enqueue_script method to add custom scripts to the admin interface.

This assumes that you have myscript.js in your plugin folder. Change accordingly. The my_custom_script handle should be unique for your module and script.

function my_enqueue($hook) {
    // Only add to the edit.php admin page.
    // See WP docs.
    if ('edit.php' !== $hook) {
        return;
    }
    wp_enqueue_script('my_custom_script', plugin_dir_url(__FILE__) . '/myscript.js');
}

add_action('admin_enqueue_scripts', 'my_enqueue');

Answer 4

<?php
function add_jquery_data() {
    global $parent_file;

    if ( isset( $_GET['action'] ) && $_GET['action'] == 'edit' && isset( $_GET['post'] ) && $parent_file == 'edit.php') {
    // Do some stuff.
    }
}

add_filter('admin_head', 'add_jquery_data');

?>