How to limit the number of lines in a multi-line textbox

Add the following JavaScript code to the Main Layout of the product. Replace XXXXX by the actual Block id

 <script>
$(document).ready(function(){
$('#InputXXXXX').keydown(function(e) {
if(e.keyCode == 13 && $(this).val().split("\n").length >= 15) {
//alert("Max of 15 lines allowed!");
return false;
}
});
});
</script>