How to detect idle time in JavaScript elegantly?

Question

Is it possible to detect \"idle\" time in JavaScript?
My primary use case probably would be to pre-fetch or preload content.

Idle time:

Answer 1

The problem with all these solutions, although correct, they are impractical, when taking into account the session timeout valuable set, using PHP, .NET or in the Application.cfc file for Coldfusion developers. The time set by the above solution needs to sync with the server side session timeout. If the two do not sync, you can run into problems that will just frustrate and confuse your users. For example, the server side session timeout might be set to 60 minutes, but the user may believe that he/she is safe, because the JavaScript idle time capture has increased the total amount of time a user can spend on a single page. The user may have spent time filling in a long form, and then goes to submit it. The session timeout might kick in before the form submission is processed. I tend to just give my users 180 minutes, and then use JavaScript to automatically log the user out. Essentially, using some of the code above, to create a simple timer, but without the capturing mouse event part. In this way my client side & server side time syncs perfectly. There is no confusion, if you show the time to the user in your UI, as it reduces. Each time a new page is accessed in the CMS, the server side session & JavaScript timer are reset. Simple & elegant. If a user stays on a single page for more than 180 minutes, I figure there is something wrong with the page, in the first place.