Edit in JSFiddle

$(document).on('change','select', function() {
	myFunction()
});
$(document).ready(myFunction);
function myFunction(){
var el = $('select');
el.toggleClass('default', !el.val());
}
<select>
  <option value="">Select value</option>
  <option value="value 1">value 1</option>
  <option value="value 2">value 2</option>
  <option value="value 3">value 3</option>
</select>
select.default {
  color: #ccc;
}

select {
  color: #000;
  height:30px;
  width:200px;
  border:1px solid #ccc;
  font-size:14px;
  padding:0 10px;
}

select option {
  color: #000;
}