var newWind = null;
function popup(url,x,y)
{
	if (parseInt(navigator.appVersion)>=4) {
		if (navigator.appName=="Netscape") {x += 16; y += 16}
		else {x += 20; y += 30}
		var winpar = "width=" + x + ",height=" + y;
		var leftPos = Math.floor((screen.width - x)/2) - 6; 
		var topPos = Math.floor((screen.height - y)/2) - 15; 
		if (leftPos < 0) leftPos = 0;
		if (topPos < 0) topPos = 0;
		winpar += ",location=0,menubar=0,resizeable=0,scrollbars=0,status=0,titlebar=0,toolbar=0,left=" + leftPos + ",top=" + topPos
		if (newWind && !newWind.closed) {
			newWind.close()
			newWind = window.open(url, "new_window", winpar)}
		else {newWind = window.open(url, "new_window", winpar)}
	}
	else {window.location = url}
}