Content Base in Javascript

[Chris Greenhill]

Hi,
I've been having some problems getting the proper base from certain web
sites.
For example, the site
http://www.summitrs.org/.
When you put that url in a browser's  address window, it will resolve to
http://www.summitrs.org/SACDHome/Page_1x.html
However, according to the response object the relative base is
'+%20strBase%20+'
There's some javascript in the page content that looks like this --
 <SCRIPT LANGUAGE="JavaScript">
  strLocation = window.location + "";
  nIndex = strLocation.indexOf("index.html");
  if (nIndex > 0)
  {
   strBase = strLocation.substring(0, nIndex);
  }
  else
  {
   strBase = window.location.href;
  }
  strBase += "SACDHome/";
  document.writeln("<BASE HREF='" + strBase + "'>");
 </SCRIPT>

What's going on here and how can I get the proper base?
 Thanks for any help,
Chris Greenhill