jBox setimage howto?

[David Shorthouse]

Hello folks,
 
    I am attempting to implement jBox and setimage since I have some pan and
zoom javascripts and am wondering how to go about passing the url query
strings as described in the jBox howto:
 
 var url;
url = ";http://www.somedomain.com/cgi-bin/mapserv";+
";?mode=map"; +
";&map="; + mapfile +
";&mapext="; + extent.join(";+";) +
";&mapsize="; + width + ";+"; + height +
";&layers="; + layerlist;
document.jBox.setimage(url);

Is this the correct format? How do I implement "extent.join"? If anyone has
a working html example template they would like to share, I would greatly
appreciate it.
 
David P. Shorthouse