I am trying to make an ajax call and I am getting the error:

TypeError: $ is undefined

This is my function.php file:


// Add custom Theme Functions here

function gear_guide_product_view( $atts ) {
    $a = shortcode_atts( array(
        'id' => '0'
    ), $atts );
    wp_register_script( 'load_product_info' , '/wp-content/themes/theme-child/js/test.js' , array( 'jquery' ) );
    wp_enqueue_script( 'load_product_info' );
    wp_localize_script( 'load_product_info' , 'para' , $atts);

add_shortcode( 'fsg' , 'gear_guide_product_view' );

this is the ajax:

function load_product_info() {
        type: 'POST',
        url: '/wp-content/themes/flatsome-child/js/controllers/get_product_info.php',
        data: para,
        dataType: 'json',
        success: function (data) {

I have declared the use of jquery and from what I read on google it's all I need in order to make an ajax call.

If there is any more information needed tell me and I'll do my best to provide it.


  • 4
    WordPress jQuery is in noConflict mode, use jQuery instead of $.
    – Milo
    Jul 31 '18 at 15:37
  • don't forget to enqueue jquery either, and consider marking an answer as accepted if it contains the correct answer, else nobody will get reputation points from comments
    – Tom J Nowell
    Jul 31 '18 at 16:24

As Milo already said in comment, jQuery is in noConflict mode in WordPress. This way other JS libraries can also use $ character...

One way to solve it is using jQuery everywhere in your JS files.

Another is to create block and define $ variable in it:

jQuery(function ($) {

    $.ajax(...); // here you can use $ since it is already defined and won’t cause conflicts


You're using very specific URLs for ajax endpoint. When you change your theme your functionality WILL break. Do check how the WP codex how to make ajax calls properly and hook into wp_ajax actions.

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