[cheesegrits]

I'm not entirely sure, but I don't think you can change a src like that. I think you have to use Image objects, like this:

<script type="text/javascript">

var lastfav;

var subfav = new Image();
var addfav = new Image();

subfav.src = 'images/thread/subfav.gif';
addfav.src = 'images/thread/addfav.gif';

// Favorites handling.
function favsprocess()
{
    if (xml.handler.readyState == 4 && xml.handler.status == 200 && xml.handler.responseText)
    {
        thisfav = document.getElementById('favs_' + lastfav);
        if (xml.handler.responseText==1)
        {
            thisfav.src = subfav.src;
            thisfav.alt = 'Remove Favourite';
            thisfav.title = 'Remove Favourite';
        } else if (xml.handler.responseText==2)
        {
            thisfav.src = addfav.src;
            thisfav.alt = 'Add Favourite';
            thisfav.title = 'Add Favourite';
        }
        
    }
}

function dofavs(threadid)
{
    xml = new vB_AJAX_Handler(true);
    xml.onreadystatechange(favsprocess);
    
    lastfav = threadid;
    xml.send('tindex.php', 'do=processfav&threadid=' + threadid);
}


</script>

Like I said, I'm not sure, but give that a go.

-- hugh