Popup - Fenster zentriert

<script language="JavaScript"> 

function a(breite,hoehe,name,pfad,prop)
{ 
xpos=(screen.width-breite)/2; 
ypos=(screen.height-hoehe)/2; 
prop+=(prop!='')?',':''; 
prop+=',left='+xpos+',top='+ypos; 

window.open(pfad,name,prop+((prop!='')?',':'')+'width='+breite+',height='+hoehe);} 

function b(breite,hoehe,name,pfad,prop)
{ 
xpos=(screen.width-breite)/2; 
ypos=(screen.height-hoehe)/2; 
prop+=(prop!='')?',':''; 
prop+=',left='+xpos+',top='+ypos; 

window.open(pfad,name,prop+((prop!='')?',':'')+'width='+breite+',height='+hoehe);} 

function c(breite,hoehe,name,pfad,prop)
{ 
xpos=(screen.width-breite)/2; 
ypos=(screen.height-hoehe)/2; 
prop+=(prop!='')?',':''; 
prop+=',left='+xpos+',top='+ypos; 

window.open(pfad,name,prop+((prop!='')?',':'')+'width='+breite+',height='+hoehe);} 

function d(breite,hoehe,name,pfad,prop)
{ 
xpos=(screen.width-breite)/2; 
ypos=(screen.height-hoehe)/2; 
prop+=(prop!='')?',':''; 
prop+=',left='+xpos+',top='+ypos; 

window.open(pfad,name,prop+((prop!='')?',':'')+'width='+breite+',height='+hoehe);} 


</script>
<br>
<br>

<!-- Hier bei allen Bilder die Fenstergröße anpassen (hier : 658, 443,) !!!!!!!!!!!! -------------------------- -->

<div align="center">
<A HREF="#" onclick="a(658,443,'popup','http://www.gloeckner-nbg.de/bild1.jpg','resizable=no,scrollbars=no, menubar=no,toolbar=no,location=no,directories=no,status=no,' )"><img src="http://www.gloeckner-nbg.de/bild1a.jpg" border="0" width="160" onFocus="this.blur()"></A>
<A HREF="#" onclick="b(658,443,'popup','http://www.gloeckner-nbg.de/bild2.jpg','resizable=no,scrollbars=no, menubar=no,toolbar=no,location=no,directories=no,status=no,')"><img src="http://www.gloeckner-nbg.de/bild2a.jpg" border="0" width="160" onFocus="this.blur()"></A>
<A HREF="#" onclick="c(658,443,'popup','http://www.gloeckner-nbg.de/bild3.jpg','resizable=no,scrollbars=no, menubar=no,toolbar=no,location=no,directories=no,status=no,')"><img src="http://www.gloeckner-nbg.de/bild3a.jpg" border="0" width="160" ></A> 
<A HREF="#" onclick="d(658,443,'popup','http://www.gloeckner-nbg.de/bild4.jpg','resizable=no,scrollbars=no, menubar=no,toolbar=no,location=no,directories=no,status=no,')"><img src="http://www.gloeckner-nbg.de/bild4a.jpg" border="0" width="160" ></A> 

</div>