function wechsel(box) {
	box.checked = box.checked ? false : true;
	box.value   = box.checked ? 1 : 0;
}

function umfrage_close(form) {

	var today = new Date();
	var yesterday = new Date(today.getTime() - 1000 * 60 * 60 * 24);
    
    form.elements["EndDate[d]"].value = yesterday.getDate();
	form.elements["EndDate[M]"].value = yesterday.getMonth() + 1;
    form.elements["EndDate[Y]"].value = yesterday.getFullYear();

	return undefined;
}

function umfrage_open(form) {

	var today = new Date();
	
    form.elements["StartDate[d]"].value = today.getDate();
	form.elements["StartDate[M]"].value = today.getMonth() + 1;
    form.elements["StartDate[Y]"].value = today.getFullYear();

	return undefined;
}