/*
prüft formularwerte
*/
function checkform(f, t)
{
	len = f.elements.length;
	err = 0;
	tofocus = null;
	for(i=0;i<len;i++)
	{
		el = f.elements[i];
		if(el.name.indexOf('*') == -1) continue;
		el.style.borderColor = '#999';
		el.style.backgroundColor = '#f8f8f8';
		y = el.type;
		v = trim(el.value);
		if(v == '') 
		{
			if(!tofocus) tofocus = el;
			err++;
			el.style.borderColor = '#f00';
			el.style.backgroundColor = '#fcc';
		}
	}

	if(err > 0)
	{
		tofocus.focus();
		alert(t);
		return false;
	}
	// datumsfelder einschalten
	document.getElementById('von').disabled = false;
	document.getElementById('bis').disabled = false;
	
	f.submit();
}

function checkListingsSearchForm(f)
{
	len = f.elements.length;
	emp = 0;
	for(i=0;i<len;i++)
	{
		if(f.elements[i].name == 'submit') continue;
		if(f.elements[i].name == 'novalue') continue;
		if(f.elements[i].value != '' && f.elements[i].value != 0) emp++;
	}
	if(emp == 0) 
	{
		alert('Please enter at least one criterium.');
		return false;
	}
	
	f.submit();
}