Fire event each time a DropDownList item is selected with jQuery

I have a dropdown: <asp:DropDownList id="dropdownid" runat="server" class=blah"/>

in my jQuery, I assign change event like this:

$('#dropdownid').change(function() {......});

Now, this works when I select different value from the dropdown, however let's say I want to select the same value again. (because I want to make another call with the same value) So, when I select it again, (without changing the value) just by clicking on the selected value from the dropdown and "selecting" it again, no event fires. Is there another event in jquery that I have to assign to it? what's the workaround?

Answer

April 25, 2014

KyleMit

A lot of the current solutions will break in a lot of situations. Any solution that relies on checking the click count twice will be very fickle.

###Some scenarios to consider:

If you click on, then off, then back on, it will count both clicks and fire.
In firefox, you can open the menu with a single mouse click and drag to the chosen option without ever lifting up your mouse.
If you use any combination of keyboard strokes you are likely to get the click counter out of sync or miss the change event altogether.
- You can open the dropdown with <kbd>Alt</kbd>+<kbd>↕</kbd> (or the <kbd>Spacebar</kbd> in Chrome and Opera).
- When the dropdown has focus, any of the arrow keys will change the selection
- When the dropdown menu is open, clicking <kbd>Tab</kbd> or <kbd>Enter</kbd> will make a selection

###Here's a more comprehensive extension:

The most robust way to see if an option was selected is to use the change event, which you can handle with jQuery's .change() handler.

The only remaining thing to do is determine if the original element was selected again.
This has been asked a lot (one, two, three) without a great answer in any situation.

The simplest thing to do would be to check to see if there was a click or keyup event on the option:selected element BUT Chrome, IE, and safari don't seem to support events on option elements, even though they are in the w3c recommendation

Inside the Select element seems to be a black box. If you listen to events on it, you can't even tell on which element the event occurred or whether the list was open or not.

The next best thing then, seems to handle the blur event. This will indicate that the user has focused on the dropdown (perhaps seen the list, perhaps not) and made a decision that they would like to stick with the original value. To continue handling changes right away we'll still subscribe to the change event. And to ensure we don't double count, we'll set a flag if the change event was raised so we don't fire back twice:

###Code:

(function ($) {
    $.fn.selected = function (fn) {
        return this.each(function () {
            $(this).focus(function () {
                this.dataChanged = false;
            }).change(function () {
                this.dataChanged = true;
                fn(this);
            }).blur(function (e) {
                if (!this.dataChanged) {
                    fn(this);
                }
            });
        });
    };
})(jQuery);

Then call like this:

$("#dropdownid").selected(function (e) {
    alert('You selected ' + $(e).val());
});

##Updated example in jsFiddle