function popup(mylink, windowname)
{
if (! window.focus)return true; 
var href;
var winX = 0;
var winY = 0;
if (parseInt(navigator.appVersion) >= 4)  {
   winX = (screen.availWidth - 800)*.5;
   winY = (screen.availHeight - 500)*.5;
}
if (typeof(mylink) == 'string') {
   href=mylink;
} else {
   href=mylink.href;
	winstyle="width=800,height=500,left=" + winX + ",screenX=" + winX + ",top=" + winY + ",screenY=" + winY + ",resizable=yes,scrollbars=yes,toolbar=yes";
	messageWindow = window.open(href, windowname, winstyle);

return false;
}
}