document.addEventListener('change', function (e) { const sel = e.target.closest('select.dropdown_product_cat'); if (!sel) return; const form = sel.closest('form'); if (form) form.submit(); }); If you are using the jQuery library, then don't forget to wrap your code inside jQuery.ready() as follows: jQuery(document).ready(function( $ ){ // Your code in here }); -- If you want to link a JavaScript file that resides on another server (similar to ), then please use the "Add HTML Code" page, as this is a HTML code that links a JavaScript file. End of comment */