OT but need guidance in timing page views

I know that this is somewhat off topic, but I just need a starting place to do the research and thought someone here might be able to help. I am developing an application in which I need to time how long a visitor remains within a module and how long they view each page. I can create the appropriate fields in MySQL and can use PHP to do the appropriate calcualtions. What I don't know is how I communicate this information to the server. I can use POST or GET statements to pass info with page turns but what do I do if the visitor leaves the site without logging out or experiences a machine crash? Also, if anyone knows of a good javascript newsgroup, please pass along the info. Thanx, Robb -- Robb Kerr Digital IGUANA Helping Digital Artists Achieve their Dreams ---------------------------------------------------- http://www.digitaliguana.com http://www.cancerreallysucks.org