You can get the API at:
http://www.techniques.org/escorte4js/escorte4js.zip
Some information about it:
http://www.techniques.org/escorte4js/escorte4js.pdf
Hope this helps.
I got this from the moodle forums: http://moodle.org/mod/forum/discuss.php?d=31216
Looks like the code is available at sourceforge: http://escorte4js.sourceforge.net/
Here is a link to the code browser
http://escorte4js.cvs.sourceforge.net/viewvc/escorte4js/core/