Question

I know that there is the change event handling in jQuery associated with an input of type select. But I want to know if the user has selected another value in the select element ! So I don’t want to run code when the user select a new element in the select but I want to know if the user has selected a different value !
In fact there are two select elements in my form and I want to launch an ajax only when the two select elements has been changed. So how to know that the two elements has been changed ?

Answer 1

You can specifically listen for a change event on your chosen element by setting up a binding in your Javascript file.

That only solves half your problem though. You want to know when a different element has been selected.

You could do this by creating a tracking variable that updates every time the event is fired.

To start with, give your tracking variable a value that’ll never appear in the dropdown.

// Hugely contrived!  Don't ship to production!
var trackSelect = "I am extremely unlikely to be present";

Then, you’ll need to set up a function to handle the change event.

Something as simple as:-

var checkChange = function() {
  // If current value different from last tracked value
  if ( trackSelect != $('#yourDD').val() )
  {
     // Do work associated with an actual change!
  }

  // Record current value in tracking variable
  trackSelect = $('#yourDD').val();
}

Finally, you’ll need to wire the event up in document.ready.

$(document).ready(function () {
  $('#yourDD').bind('change', function (e) { checkChange() });
});