Question

When you mark/unmark the checkbox I want it to window.location = index.php?mark=1 if it’s marked, and if you click and it gets unmarked it should be mark=0

Answer 1

$('input:checkbox').click(function(){
  window.location='/index.php?mark=' + ($(this).attr('checked') ? 1 : 0);
});

Should do the trick, but note that means it’s going to cause a page reload between checks.

EDIT or as William mentioned, you can bind to .change() as well.

EDITv2 Working example: http://www.jsfiddle.net/T5CaC/