var newWindow;

function displayPopup(pageName, pageWidth, pageHeight) {
	if (newWindow != null) {
		if (!newWindow.closed) {
			newWindow.close();
		}
	}
 
	availableHeight = screen.availHeight;
	availableWidth  = screen.availWidth;
 
	midHeight = availableHeight / 2;
	midWidth  = availableWidth / 2
 
	windowX = Math.floor(midWidth - (pageWidth / 2));
	windowY = Math.floor(midHeight - (pageHeight / 2));
  
	browserType = navigator.appName.toLowerCase();

	if (browserType.indexOf("netscape") >= 0) {
		XPosString = "screenX=" + windowX + ",";
		YPosString = "screenY=" + windowY + ",";
	}
	else if (browserType.indexOf("microsoft") >= 0) {
		XPosString = "left=" + windowX + ",";
		YPosString = "top=" + windowY + ",";
	}
	else {
		XPosString = "";
		YPosString = "";
	} 
  
	eval("newWindow = window.open(pageName,'information','location=no,menubar=no,resizable=yes," + XPosString + YPosString + "scrollbars=yes,status=no,toolbar=no,width=" + pageWidth + ",height=" + pageHeight + "')");
	newWindow.focus();

	return false;

}