function open_window(aPage,aWidth,aHeight,aLeft,aTop) {		
	if (!aWidth)
		aWidth = 480;
	if (!aHeight)
		height = 350; 
	if (!aLeft)
		aLeft = 400;
	if (!aTop)
		aTop = 200; 
		
	OpenWin = window.open(aPage, "window", "toolbar=no,menubar=no,location=no,scrollbars=no,resizable=no,width=" + aWidth + ",height=" + aHeight + ",left=" + aLeft + ",top=" + aTop + "");
}