wp_localize_script, variable is not defined in jquery

wp_localize_script should be called AFTER wp_enqueue_script:

IMPORTANT!: wp_localize_script() MUST be called after the script it’s
being attached to has been enqueued or registered. It doesn’t put the
localized script in a queue for later scripts.

Fix it in your function:

function my_action_callback() {
wp_enqueue_script('jscustom'); // I assume you registered it somewhere else
wp_localize_script('jscustom', 'ajax_custom', array(
   'ajaxurl' => admin_url('admin-ajax.php')
));

}

You can always check in your page’s <head> if you see your variable.

Related Posts:

  1. JSON parsing error syntax error unexpected end of input
  2. jQuery Ajax error handling, show custom exception messages
  3. My javascript is returning this error: $.ajax is not a function
  4. Ajax TypeError: $.POST is not a function
  5. TypeError: $.ajax(…) is not a function?
  6. XML Parsing Error: not well-formed in FireFox but good in Chrome
  7. How to get a cross-origin resource sharing (CORS) post request working
  8. jQuery Form Validation before Ajax submit
  9. jQuery – Illegal invocation
  10. jQuery ajax error function
  11. ajax stopped working when not logged in?
  12. Using jQuery to delete data stored in wp_options
  13. AJAX nonce with check_ajax_referer()
  14. wp_mail script with jQuery post
  15. Ajax call does not activate callback function
  16. AJAX call returns 0
  17. jQuery and AJAX Not working with Select Form Element
  18. How to pass both action and formdata in wordpress ajax?
  19. jquery & ajax getting data to php in wordpress
  20. AJAX returns response 0
  21. Basic WordPress AJAX Call
  22. AJAX post into pop-up div
  23. Bind to WPSetAsThumbnail
  24. Appending anchor tag to next post
  25. How to load whole WordPress pages dynamically with AJAX/jQuery like this following website?
  26. Creating custom AJAX requests
  27. How to pass jQuery ajax URL value
  28. Registration e-mail check with AJAX
  29. Cannot access elements of json object
  30. Basic ajax call in WordPress
  31. Updating User Profile with AJAX not working
  32. how to get the comment ID in the front end when the REPLY button is clicked?
  33. Auto Load New Posts
  34. Admin wp_ajax hook returning 0
  35. wp_ajax() question.. not using wp_enqueue_script?
  36. wp_ajax unauthenticated and authenticated
  37. Showing Author Information and Latest Post by author in lightbox when clicked on the name of the author
  38. WordPress ajax function parameter value not being passed
  39. wp_verify_nonce not working
  40. WordPress customizer refresh screen after save
  41. Is there a restriction in WP on the use of jQuery load function?
  42. Load created php file data via ajax
  43. Display data on same page as form without refresh
  44. Ajaxify calendar
  45. Error when posting comment form: The error is TypeError: e[h] is not a function
  46. Ajax, Permalinks and post_thumbnail
  47. How to Dynamically Load Content Into Body of Bootstrap Modal Window?
  48. Return an array from get_terms and store as JavaScript array for search autocomplete
  49. Frontend Post with JQuery AJAX to Php Issue
  50. WP http XML response HTML encoding and image display problems
  51. Using WP_Query to grab custom meta values, foreach to json object
  52. First Attempt at AJAX and it keeps getting Canceled. Can’t Get Results to Show
  53. Passing a varible from jQuery to PHP
  54. videopress videos are not displayed when loading the content with ajax in a lightbox
  55. Retrieve post info within AJAX helper function
  56. How to return multiple arguments from AJAX callback function
  57. Display posts from another site using REST API in an asynchronous manner
  58. Ajax form submit not working, returns 0
  59. Why does my jQuery AJAX return 0?
  60. Simplest ajax form not working when it should
  61. Loading dynamic content with AJAX breaking jQuery
  62. why is my wordpress Jquery-Ajax call not working?
  63. How to retrieve WP_Object that is inside an array of another array
  64. fill form fields with ajax response
  65. Adding custom cart price with Ajax in wordpress
  66. No Object Properties sending form through AJAX
  67. Redirect wp_dropdown_pages() to an AJax request?
  68. Can’t add classes using jQuery from a JSON string with get_body_class()
  69. Ajax call through admin-ajax.php returns 404 error
  70. WordPress Insert not working with ajax
  71. Search query with Ajax
  72. WP AJAX API with JS file
  73. admin ajax php success returns 0
  74. Why is ajax working on one server and not the next?
  75. Is there some jQuery conflict here?
  76. How to use wp_update_post with ajax on frontend
  77. Getting jQuery AJAX to work in WordPress (getting -1)
  78. Connect Agile Carousel to WordPress AJAX
  79. AJAX calendar navigation returns -1
  80. Which hook to use when adding ajax to viewer-facing side?
  81. my example with ajax doesn’t work
  82. jQuery forms & updating info
  83. Orderby post__in Not Working Correctly?
  84. jQuery.post() calling function with parameter
  85. $_POST empty in using new php file added to theme
  86. Passing variable data from external jQuery file to options.php
  87. Retrieve customizer value using ajax or customizer api and print the value in theme
  88. Displaying contents of a tab
  89. owl carousel not working after ajax load [duplicate]
  90. WordPress version for this autocomplete jQuery code
  91. Ajax autocomplete based on usercode
  92. Variable not being returned from Ajax Javascript (though javascript receives it)
  93. jQuery AJAX add json2 dependency?
  94. How to respond with WP_Ajax_Response();
  95. How to pass more information though separate post keys via AJAX
  96. Loop not appending through infinite-scroll ajax call
  97. Get selected value with PHP and jQuery
  98. How to combine jQuery in-place editor with $wpdb->update
  99. Load loop images on click / defer image loading until click or other event
  100. Widget won’t work due to old JavaScript? Any ideas how to make it work? [closed]