<form action="product.php" method="get" name="frmProduct" id="frmProduct" enctype="multipart/form-data">
<input onclick="submitAction()" id="submit_value" type="button" name="submit_value" value="">
submit is not a function
means that you named your submit button or some other element
submit. Rename the button to
btnSubmit and your call will magically work.
When you name the button submit, you override the
submit() function on the form.