String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g, ''); }

function isValidEmail(email) {      
      var regex = /^([a-zA-Z0-9_\.\'\-\+])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
      return regex.test(email.trim());
}