Pop up centrato con apertura al clik

nel <head>

code:--------------------------------------------------------------------------------

<script language="JavaScript">
function ApriFinestra(str) {

larg=300;
alt=350;
toptop=(screen.height/2)-(alt/2);
leftleft=(screen.width/2)-(larg/2);

searchWin = window. open(str,'','top='+toptop+',left='+leftl
eft+',scrollbars=no,width='+larg+',heigh
t='+alt+',status=no,location=no,toolbar=
no');


}

</script>

--------------------------------------------------------------------------------


nel <body>

code:--------------------------------------------------------------------------------
<a href="java script:;"
onClick="ApriFinestra('popup1.html', '', 'width=300,height=350, status=no, scrollbars=no');">
<p align="center">PRIMO POPUP</a> </p>