function centerWindow(page, varWidth, varHeigth) {
	if (document.all)
		var xMax = screen.width, yMax = screen.height;
	else
		if (document.layers)
			var xMax = window.outerWidth, yMax = window.outerHeight;
		else
			var xMax = 640, yMax=480;

	var xOffset = (xMax - varWidth)/2, yOffset = (yMax - varHeigth)/2;

	window.open(page,'','width='+varWidth+',height='+varHeigth+',screenX='+xOffset+',screenY='+yOffset+', top='+yOffset+',left='+xOffset+'');
}