per default it’s like this:

<input type="checkbox" name="checkbox_group_'.$groupname.'" id="checkbox_group_'.$groupname.'" class="custom checked" data-mini="true" value="0" checked="true"/>
<label for="checkbox_group_'.$groupname.'">'.$groupname.'</label>

programmatically it’s like this:

$(document).ready(function() {
	$("input[type=checkbox]").attr("checked",true).checkboxradio("refresh");
	$('#checkbox_group_default').checkboxradio('disable'); // if you want to disable the checkbox (grey out)
});
admin