function popup(mylink, windowname){
	if (! window.focus)return true;
	var href;
	if (typeof(mylink) == 'string')
	   href=mylink;
	else
	   href=mylink.href;
	
	var width = 450;
	var height = 490;
	var left = Math.floor(((screen.availWidth) / 2)-(width/2));
	var top = Math.floor(((screen.availHeight) / 2)-(height/2));

	window.open(href, 'name', 'width=450,height=490,scrollbars=yes,left='+left+',top='+top);
	return false;
}