jquery email validation

email-validation.js

$('#cases-email').keyup(function(){
    var email = $('#cases-email').val();
    var filter = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    if (!filter.test(email)) {
      //alert('Please provide a valid email address');
      $("#cases-error-email").text('Please enter a valid email.');
      $('#support-contact-cases .button').attr('disabled', true);
      email.focus();
      //return false;
    } else {
        $('#cases-error-email').text('');
        $('#support-contact-cases .button').attr('disabled', false);
   }
});