jquery .prop('checked'); auto check code example
Example 1: Setting “checked” for a checkbox with jQuery
$('.myCheckbox').prop('checked', true);
$('.myCheckbox').prop('checked', false);
Example 2: 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