// Opens a page in a popup.
// The url that will be opened is the "url" parameter of this function.
function OpenPopup(url, width, height, windowName)
{
	options = 'toolbar=no,menubar=no,location=no,directories=no,status=no,scrollbars=yes,resizable=no,copyhistory=no';
	//alert(options);
	options += ',width=' + width + ',height=' + height;
	if (window.screen)
	{
		windowLeft = (screen.availWidth - width)/2;
		windowTop = (screen.availHeight - height)/2;
		options += ',left=' + windowLeft + ',top=' + windowTop;
	}
	newwindow = window.open(url,windowName,options);
	newwindow.opener = this;
	newwindow.focus();
}