var piWin = null;
function piview(url,w,h)
{
		if(piWin != null && !piWin.closed ) piWin.close();
		piWin = window.open(url,'piview','toolbar=0,location=0,status=0,menubar=0,scrollbars=0,left='+(screen.availWidth-w)/2+',top='+(screen.availHeight-h)/2+',width='+w+',height='+h+'');
		if(!piWin.focus()) piWin.focus();
}