That is exactly what it is doing. For instance, let's say you're using IIS and the root for your web page is in c:\inetpub\wwwroot\myapp. You likely have a file in there called index.html (or index.php etc. etc.). When you use a *relative path*, it will start at the root directory of the web. Try to stay away from fully qualified paths (such as C:\my\path\my.file) as you will likely run into permission issues. If you specify the path "files/data.dat" then you will actually be referencing the file c:\inetpub\wwwroot\myapp\files\data.dat. I can't really define what a relative path is any clearer than that.