Valid Email with JS

validEmail.html

<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
<form>
<label for="regExField">Email: </label>
  <input id="regExField" type="text">
  <span id="messageExField"></span>
</form>
<script type="text/javascript">
$(document).ready(function () {
  function checkEmailValid(str) {
      var regEx = /^.{1,}@.{2,}\..{2,}/;
      return str.match(regEx);
  }
  $( "#regExField" ).keyup(function() {
    var valText = $(this).val(); 
    if(checkEmailValid(valText))
    { 
    	$('#messageExField').html('Email valid')
    } else { 
      $('#messageExField').html('Email not valid') 
    }
  });
});
</script>