function popup(url,name,w,h) {
	
	if (screen.width < w) { w = screen.width }
	if (screen.height < h) { h = screen.height }
	
	var l = (screen.width-w)/2;
	var t = (screen.height-h)/2; 
	pop = window.open(url,name, 'width='+ w +',height='+ h +',top='+ t +',left='+ l +',resizable=1,status=1,menubar=1,toolbar=1,scrollbars=1,location=1,directories=1');
	
	if (pop) { if (parseInt(navigator.appVersion) >= 4) { pop.focus(); } } 
	else { alert('A popup was blocked by your browser.'); }
	
}