jquery get value of unchecked checkbox code example

Example 1: jquery set checkbox checked unchecked

//jQuery 1.6+ use
$('.checkbox').prop('checked', true);  //false for uncheck
//jQuery 1.5.x and below use
$('.checkbox').attr('checked', true);  //false for uncheck

Example 2: jquery check if all checkbox is not checked

$('#checkAll').click(function () {    
     $('input:checkbox').prop('checked', this.checked);    
 });