function setzip(e,t) {
	if(!t)return;
	var v = t.value;
	
	if(v.length == 5)
	{
		//alert(t.value);
		xmlhttpPost("zip.php","zip="+t.value,getzip);
	}
	document.getElementById('city').value='';
}
function getzip(response)
{
	document.getElementById('city').value = response;
}