Can anyone help me convert VBscript to Javascript

[Atari78]

I'm trying to convert my VB Script to a Javascript. This is very important to me because VB script is not supported anymore. Please can someone help me?

<script language=VBSCRIPT> <!--
      function geturl(nRep)
      dim url
      dim sFrom
      dim sTo
      sFrom = year(date()-7) & "-" & right("00" & month(date()-7),2) & "-" & right("00" & day(date()-7),2)
      sTo = year(date()) & "-" & right("00" & month(date()),2) & "-" & right("00" & day(date()),2)
       select case nRep
       case 1
             url = "" & sFrom & "&DateStartEnd_To=" & sTo
       case 2
             url = "URL" & sFrom & "&DateStartEnd_To=" & sTo
       case 3
             url = "URL" & sFrom & "&DateStartEnd_To=" & sTo
       end select
       geturl = url
      end function
     --> </script>

[Dormilich]

can you explain what this script is supposed to do?