$.fn.checkboxState = function(mode) {
	var mode = mode || 'on'; // if mode is undefined, use 'on' as default
	var checkboxes = this.find("input[@type='checkbox']");
	if(!checkboxes) {return this};
	return this.each(function() {
		switch(mode) {
			case 'on':
				checkboxes.each(function() {
					this.checked = true;
				});
				break;
			case 'off':
				checkboxes.each(function() {
					this.checked = false;
				});
				break;
		}
	});
};