function mypopup(url,w,h)
{ 
	w = w ? w : 600;
	h = h ? h : 600;
	t = screen.availHeight/2 - h/2;
	l = screen.availWidth/2 - w/2;
	window.open(url,'search','width='+w+',height='+h+',top='+t+',left='+l+',toolbars=no');
}