jQuery difference between change and click event of checkbox

The main difference: when you click / hit space on a focused checkbox first the click event fired, with no changes. At this point you can still prevent the default action (with event.preventDefault()) which would be to toggle the checked state of that checkbox, and fire the change event (which hasn't got default action).

In some browsers the change event will fire only after the first blur after the click.

I would guess that change fires when the checkbox changes (even if you don't click on it). Eg if you change the checkbox's state via some other function.

According to the W3C, the onclick event is triggered by the keyboard for accessibility purposes:

SCR35: Making actions keyboard accessible by using the onclick event of anchors and buttons

In order to provide a better user experience for those without the use of a mouse, browsers have been developed to fire the onclick event even if the click occurs with a keyboard.

For this reason, jQuery's click event will fire even if the checkbox is clicked by using the keyboard's spacebar. change, obviously, will fire every time the checkbox's state changes.

The checkbox just happens to be the special case where change and click are interchangable, because you can't fire the change event without also triggering click.

Of course, the exception to this rule is if you were to use javascript to manually alter the checkbox, such as:

/* this would check the checkbox without firing either 'change' or 'click' */
$('#someCheckbox').prop('checked',true);

/* this would fire 'change', but not 'click'. Note, however, that this
   does not change the checkbox, as 'change()' is only the function that
   is fired when the checkbox changes, it is not the function that
   does the changing  */
$('#someCheckbox').trigger('change');

/* this would fire 'click', which by default change state of checkbox and automatically triggers 'change' */
$('#someCheckbox').trigger('click');

Here's a demonstration of these different actions: http://jsfiddle.net/jackwanders/MPTxk/1/

Hope this helps.