jQuery is not defined in Wordpress, but my script is enqueued properly

Question

I am trying to load a separate javascript file mobile-menu.js to my Wordpress theme. When I look at the console, it says, "jQuery is not defined." However, I know that I enqueued my script files correctly. Any ideas?

HTML file:

<a href="#" id="menu-icon"></a> <!--this line wasn't here originally-->
    <div id="switchmenu"><!--switchmenu begin-->
        <?php wp_nav_menu( array( 'theme_location' => 'primary' ) ); ?>
    </div><!--switchmenu end-->

functions.php file:

function lapetitefrog_scripts() {
    wp_enqueue_style( 'lapetitefrog-style', get_stylesheet_uri() );
    wp_enqueue_script( 'lapetitefrog-mobile-menu', get_template_directory_uri() . '/js/mobile-menu.js', array(), '1.0', true );
}
add_action( 'wp_enqueue_scripts', 'lapetitefrog_scripts' );

mobile-menu.js file:

 jQuery(document).ready(function($) {
    $('#menu-icon').click(function() {
            $('#switchmenu').slideToggle("fast");
    });
});

Waikiki

Try this : jQuery(document).ready(function() { jQuery('#menu-icon').click(function() { jQuery('#switchmenu').slideToggle("fast"); }); }); – Exile

Check if you have two jquery files included in same page. – Spectrohelioscope

Answer 1

Add wp_enqueue_script('jquery'); before you enqueue your scripts. 

Stereotyped

This worked! Thank you so much! I find this issue to have been very strange, because I've never had to add that bit of code to my scripts before...would you happen to know why it is necessary this time? Thanks! – Waikiki

Uhm, It's just how I understand how it works following the wordpress codex and support forums, so right from the start have I put it in my plugins and themes, without ever questioning it. There are a few others as well, eg wp_print_scripts('editor'); if you wish to use wp_edit.... I just add them by default depending on what code snippets I have for what purpose. Sorry I cannot elaborate more. – Stereotyped

@GavinSimpson Where is the functions.php file? Inside the "wp-content/themes" right? If so, which one should I change? There are 2 functions.php, one inside the normal folder and another inside a -child folder. – Clipper

use the one inside the theme folder you are using, so if you are using the child theme then edit the one in themes/mytheme-child. – Stereotyped

This answer has saved me hours of work. Thank you so much. – Codeine

Answer 2

First Make sure that jquery file is include in the header, and your file requied jQuery

wp_enqueue_script( 
        'lapetitefrog-mobile-menu', 
        get_template_directory_uri() . '/js/mobile-menu.js', 
        array('jquery'), 
        '1.0', 
        true 
);

Second you should start your javascript file like:

(function($) {
    $(document).ready(function() {
        .......
    });
})(jQuery);

OR

// Use jQuery in place of $
jQuery(document).ready(function() {
    .....
});

Oratorio

Adding the 'jquery' in the array() seems to have gotten rid of the jQuery undefined problem. But now when I check the net panel, it doesn't even get the mobile-menu.js file. What could be wrong? – Waikiki

@Waikiki Check in the footer, you define the option true in wp_enqueue_script() – Oratorio

Nope, it isn't there. – Waikiki

Answer 3

You can try:

enqueue Jquery first.

wp_enqueue_script('jquery'); 

and then enqueuing the latter script with JQuery dependency in 3rd argument i.e array('jquery') that's what mostly people forget.

wp_enqueue_script( 'lapetitefrog-mobile-menu', get_template_directory_uri() . '/js/mobile-menu.js', array('jquery'), '1.0', true );

Nonet

I am creating my own plugin, and get this error loading my custom jquery because i think jquery library is not loaded in resource page and this solution didnt help me! actually i need to load jquery in admin panel! do you know other solution? – Commoner

Answer 4

Wordpress ships with jQuery by default

// Adds jQuery
    add_action('init', 'childoftwentyeleven_down');

        function childoftwentyeleven_down() {

          // register your script location, dependencies and version
                wp_register_script('down',
                    get_stylesheet_directory_uri() . '/js/down.js',
                    array('jquery') );
           // enqueue the script
           wp_enqueue_script('down');

        }

Diptych

Answer 5

The error jQuery is not defined might also appear with jQuery code embedded in your template parts.

This happens when jQuery is added to the footer of the page, while the embedded script tries to execute in the middle of the page.

If this is the case, you need to load jQuery in the header with wp_enqueue_script(). So the last parameter needs to be false here:

wp_enqueue_script( 'my-jquery', get_template_directory_uri() . '/js/jquery.js', array(), time(), false );

Now the code executes in the right order and jQuery will be defined.

Another solution would be to move the embedded script to a Javascript file that will also be added with wp_enqueue_script() to the footer of the page. This is up to you.

Andria

In WP, jQuery always appears in the header unless you have taken purposeful steps to relocate it. – Ringworm

Incorrect. This totally depends on how your WordPress theme is built. – Andria

Floris, that's exactly what I meant by "taking purposeful steps to relocate it". The vast majority of themes do indeed include jQuery in the header. Perhaps I shouldn't have used the word "always". – Ringworm