function checkAll(field) {
	var countCheckBoxes = field.length;
	if(!countCheckBoxes) {
		field.checked = true;
	} else {
		for (i = 0; i < field.length; i++)
			field[i].checked = true;
	}
}

function uncheckAll(field) {
	var countCheckBoxes = field.length;
	if(!countCheckBoxes) {
		field.checked = false;
	} else {
		for (i = 0; i < field.length; i++)
			field[i].checked = false;
	}
}