intercept form and submit it via ajax (requires jQuery)

ajaxSubmit.js

function _noop() {}
function _constant(v) { return function() { return v; }; }

/**
 * intercept <form> and submit it via XHR
 * @param {String} formSelector
 * @param {Function} successCallback
 * @param {Function} errorCallback
 * @param {Function} beforeSubmit
 */
function AjaxSubmit(formSelector) {

    var successCallback = arguments[1] || _noop;
    var errorCallback = arguments[2] || _noop;
    var beforeSubmit = arguments[3] || _constant(true);

    $(document).on('submit', formSelector, {
        onSuccess: successCallback,
        onError: errorCallback
    }, onSubmit);

    function onSubmit(evt) {
        evt.preventDefault();

        if (! beforeSubmit.call(this) ) return false;

        var $form = $(this);
        $.ajax({
            type: $form.attr('method'),
            url: $form.attr('action'),
            data: $form.serialize(),
            success: evt.data.onSuccess.bind(this),
            error: evt.data.onError.bind(this)
        });

        // to stop propagation
        return false;
    }
}