/* BEGIN CUSTOM CODE THE REFERENCE */
$.validator.addMethod(
    "regularExpression",
    function (value, element, regexp) {
        var check = false;
        var re = new RegExp(regexp);
        return this.optional(element) || re.test(value);
    },
    "Please check your input."
);
String.prototype.trim = function () { return $.trim(this) } //IE trim() fix
/* END CUSTOM CODE THE REFERENCE */