function checkEmail(form, field)
{
	reg_ex5=/^\w[\w|\.|\-]+@\w[\w|\.|\-]+\.[a-zA-Z]{2,4}$/;
	return (reg_ex5.test(getField(form, field).value))
}
function checkField(form, field)
{
	return (getField(form, field).value!="");
}
function checkCheck(form)
{
	if ( !checkField(form, '_check2') )
	{
		return false;
	}
	if ( parseInt(getField(form, '_check1').value)+3 != parseInt(getField(form, '_check2').value) )
	{
		alert('Ihre Rechnung von '+getField(form, '_check1').value+' plus 3 ist falsch!');
		return false;
	}
	return true;
}
function formAlert(bool, msg) {
	if (! bool) {
		alert(msg);
	}
	return bool;
}

function getField(form, name) {
	return document.forms[form].elements[name];
}