利用 jquery 避免重複 submit

(function ($) {
// jQuery plugin to prevent double submission of forms
$.fn.preventDoubleSubmission = function () {
    $(this).on('submit', function (e) {
        var $form = $(this);

        if ($form.data('submitted') === true) {
            // Previously submitted - don't submit again
            e.preventDefault();
        } else {
            // Mark it so that the next submit can be ignored
            $form.data('submitted', true);
        }
    });

    // Keep chainability
    return this;
};
})(jQuery);

$("form").preventDoubleSubmission();