function popupwindow(url,h,w,number)
{
	theHeight = h;
	num = number;
	XPosition = screen.availWidth/2 - w/2;
	YPosition = (screen.availHeight/2 - theHeight/2);
	newwindownum= window.open(url, "newwindow"+num+"", "toolbar=no,menubar=no,scrollbars=yes,resizable=yes,location=top,status=no,width="+w+",height="+theHeight+",ScreenX=0,ScreenY=0,Top="+YPosition+",Left="+XPosition);
	newwindownum.focus()
}