I think you're having trouble putting things in the footer because that template is actually evaluated in global.php at the beginning of member.php. Is there a reason those need to be in the footer? You could probably put them somewhere else and have it work. Also, you have the part worked out that gets the value in js, but I think you could also do something like:
Code:
<script type="text/javascript">
var jusrerpc = $bbuserinfo[field6];
</script>
in a template and not have to do any special js (although I guess the above needs some quotes if it's a string value).
In any case, the javafields line would need curly braces like this:
Code:
<div id='JUSERLOC' style='display:none;'>{$vbulletin->javafields['fullLocation']}</div>
and the other $bbuserinfo line you had a problem with needs the single quotes removed (or it may also work if you surrounded it with curly braces).
But like I said, I don't think it'll work in the footer. If you really need it there you might be able to find a way to do it in an earlier hook in global.php.