Same problem here!!!
And also you miss a ] in your code, line 329
Change this:
var wc_qb_product_id = jQuery("'.$variable_form_class.' input[name=\"variation_id\"").val();
To this:
var wc_qb_product_id = jQuery("'.$variable_form_class.' input[name=\"variation_id\"]").val();.
And tks for this plugin!!!
@duvanmonsa, this answer is gold, tks for share, this answer must be in stackoverflow
