I am new to Javascript so naturally I am having some issues with inputting the code correctly to get the behavior I want.   I have two fields (Current and Previous MPG). I need for an alert to display if the Current MPG is less than the Previous MPG. With some assistance from a colleague I input this into the JS field. But when I test I do not see the alert displayed.

Am I missing something or am I doing this incorrectly?

 $('#q671 input').change(function () {
    var x = $('#q671 input').val();
    var y = $('#q672 input').val();


    if (x > y) {
          alert("Current fuel economy must be higher than Previous fuel economy");
          return false;
    }
})


$('#q672 input').change(function () {
    var x = $('#q671 input').val();
    var y = $('#q672 input').val();


    if (x > y) {
          alert("Current fuel economy must be higher than Previous fuel economy");
          return false;
    }
})