A simpler solution is to do this rather than using uniform:
$('#check1').prop('checked', true); // will check the checkbox with id check1
$('#check1').prop('checked', false); // will uncheck the checkbox with id check1
This will not trigger any click action defined.
You can also use:
$('#check1').click(); //
This will toggle the check/uncheck for the checkbox but this will also trigger any click action you have defined. So be careful.
EDIT: jQuery 1.6+ uses prop() not attr() for checkboxes checked value