Goto Detail Page to PopUp Window

I have a page with a repeat region in ASP VBScript. I want to use a Goto Detail Page but to open a PopUp Window with Javascript. This doesn't work for me, as it always goes to the first record:

<script>
function opencalinterval(){
var popurl="/en/calcenter/equipment/edit_calinterval.asp?<%= Server.HTMLEncode(MM_keepNone) & MM_joinChar(MM_keepNone) & "id=" & rsAssets.Fields.Item("id").Value %>"
winpops=window.open(popurl,"","width=600,height=500,scrollbars,")
}
</script>

It works if I use it on a regular hyperlink like this:

<a href="/en/calcenter/equipment/edit_calinterval.asp?<%= Server.HTMLEncode(MM_keepNone) & MM_joinChar(MM_keepNone) & "id=" & rsAssets.Fields.Item("id").Value %>">change</a>