jquery.validate - Birthday Date Format
$.validator.addMethod("birthday_date", function (value) {
// var pattern = /\d{2}\/\d{2}\/\d{4}/;
// var pattern = /1?[0-9]\/[1-3]?[0-9]\/[0-9][0-9][0-9][0-9]/;
var pattern = /^([0-9]|1[0-2])\/([0-9]|1[0-9]|2[2-9]|3[0-1])\/[0-9][0-9][0-9][0-9]$/;
return pattern.test(value);
}, "Please enter your birthday as MM/DD/YYYY.");