CODE EXAMPLE FOR JAVASCRIPT

listen to changes in children of div in html

$('#product_descriptioncontent').children().each(function() {
    $(this).on('keyup', function() {
        if ($(this).data('c_val') != $(this).val()) {
            alert('value changed!');
            //do other stuff
        }
        $(this).data('c_val', $(this).val());
    }).data('c_val', $(this).val());
});