Parselyjs provides the default validation of many common scanrios such as email,url, minlength, maxlength,digits, date etc. It also provide remote valdation easy. you can use remote method to validate weather your required field is valid or not. The library also provide support to add custom validator according to your requirements.
The error messages of parsleyjs can be customized easily with little css haeadce. It is a well documented and also support localization.