<!-- POPUP ANFANG -->
function popup(url, w, h)
{
   var padding;
   <!-- Explorer -->
   (navigator.appName == "Microsoft Internet Explorer") ? (padding = 5) : (padding = 0);
	
   <!-- zentriert -->
   var screenw = screen.availWidth;
   var screenh = screen.availHeight;
   var winw = (w + 15 + padding);
   var winh = (h + 15 + padding);
   var posx = (screenw / 2) - (winw / 2);
   var posy = (screenh / 2) - (winh / 2);

   var win = window.open(url,"popup","top="+posy+",left="+posx+",width="+winw+",height="+winh+",menubar=no,locationbar=no,statusbar=no,resizable=no,toolbar=no,dependent=yes,scrollbars=yes");
   win.focus();
  
} 
<!-- POPUP ENDE -->

<!-- PASSWORT ANFANG -->
 function passwort() 
 { 
var eingabe = window.prompt("Bitte Passwort eingeben","");
document.location.href = eingabe + ".html";
 }
 <!-- PASSWORT ENDE -->