http://www.w3schools.com/tags/att_a_href.asp defines the attributes for urls that can be used with the href declaration in an anchor tag. I have been using a relative attribute as set out in that definition within a web site in the form "<a href="ref-mt.html#006">MT006</a>" where the html file called is in the same directory on the web site as the page containing the call. IE and Safari expand this call correctly to "http://www.s-r-s.org.uk/railref/ref-mt.html#006" and the link works as intended. Firefox does so as well when I use my local copy to test before uploading to the web site, BUT Firefox fails to expand correctly when working from the live web site. In these circumstances it expands the call to "http://www.s-r-s.org.uk/ref-mt.html#006" which does not work (page not found error) because the file is not in the root directory of the web site. Interestingly if I alter the HTML code to <a href="../railref/ref-mt.html#006">MT006</a> Firefox does work correctly and, once that call is made it correctly expands all the other similar calls which remain in the form "<a href="ref-mt.html#006">MT006</a>". Why does the expansion fail in this way?