moving images breaks relative path

var webpageBaseHref = document.location.href.substring(0, document.location.href.lastIndexOf('/') + 1);
var webpageBasePath = document.location.pathname.substring(0, document.location.pathname.lastIndexOf('/') + 1);
var editorPath = '/fckeditorTest/fckeditor/';

var editortest = new FCKeditor('editortest');
editortest.BasePath = editorPath;
editortest.Config['BaseHref'] = webpageBaseHref;
editortest.Height = 700;
editortest.Value = 
   'This is some <strong>sample text</strong>. You are using <a href="http://www.fckeditor.net/">FCKeditor</a>.<br />' +
   '<img src="userfiles/image/test.gif" /><img src="userfiles/image/test.jpeg" /><br /><br /><br />webpageBaseHref = ' + unescape(webpageBaseHref) + '<br />webpageBasePath = ' + unescape(webpageBasePath);
editortest.Create();