How can I easily maintain checkbox state?

How can I easily maintain checkbox state upon refresh?

Really need a clear how-to example on this. My site can be viewed here: HERE !

That isn't a standard version of Custom Properties, is it? (as far as I know there's no way to have the 'Select / Unselect All' checked by default).

Try without the js script you addedd (// All Region checkboxes checked by default
$("input[name='cp_region[]']").prop("checked", true); ...) and set the values you want in checked state as default.

Yes, it is the standard version of Custom Properties, with a bit of custom JavaScript to get the functionality I'm looking for. I was able to create it select unselect all checkbox. what I'm looking for is the ability to maintain checkbox state upon page reload. This should be doable via cookies and JavaScript.

Concerning your recommendation below, I'm only allowed to select one checkbox as the default in the backend. I use JavaScript to select all checkboxes by default.

I'm only allowed to select one checkbox as the default

Nope, you *were* only allowed to select one checkbox as the default. Starting from version 2.0.6 *more* fields can be set as default.

Achieving the same results working only on the client side (js + cookie) is not easy / reliable at all. You need to store the state of each control before form submission, then retrieve that from the cookie when the page reloads, compare with checked boxes on new page, figure out if user has done any selections, decide if you need to restore the default state, ... to sum it up: you are entering in a world of pain

Sounds like a great challenge to me! I'll let you know when it's done.