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

(Partially inspired by the good core logic of Equiman earlier in this thread.)

sessionExpiration.js

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sessionExpiration.js is lightweight yet effective and customizable. Once implemented, use in just one row:

sessionExpiration(idleMinutes, warningMinutes, logoutUrl);

• Affects all tabs of the browser, not just one.
• Written in pure JavaScript, with no dependencies. Fully client side.
• (If so wanted.) Has warning banner and countdown clock, that is cancelled by user interaction.
• Simply include the sessionExpiration.js, and call the function, with arguments [1] number of idle minutes (across all tabs) until user is logged out, [2] number of idle minutes until warning and countdown is displayed, and [3] logout url.
• Put the CSS in your stylesheet. Customize it if you like. (Or skip and delete banner if you don't want it.)
• If you do want the warning banner however, then you must put an empty div with ID sessExpirDiv on your page (a suggestion is putting it in the footer).
• Now the user will be logged out automatically if all tabs have been inactive for the given duration.
• Optional: You may provide a fourth argument (URL serverRefresh) to the function, so that a server side session timer is also refreshed when you interact with the page.

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This is an example of what it looks like in action, if you don't change the CSS.

Answer 2

I have created a small lib that does this a year ago:

https://github.com/shawnmclean/Idle.js

Description:

Tiny javascript library to report activity of user in the browser (away, idle, not looking at webpage, in a different tab, etc). that is independent of any other javascript libraries such as jquery.

Visual Studio users can get it from NuGet by: PM> Install-Package Idle.js

Answer 3

Here is a rough jQuery implementation of tvanfosson's idea:

$(document).ready(function(){

   idleTime = 0;

   //Increment the idle time counter every second.
   var idleInterval = setInterval(timerIncrement, 1000);

   function timerIncrement()
   {
     idleTime++;
     if (idleTime > 2)
     {
       doPreload();
     }
   }

   //Zero the idle timer on mouse movement.
   $(this).mousemove(function(e){
      idleTime = 0;
   });

   function doPreload()
   {
     //Preload images, etc.
   }

})

Answer 4

Here is a simple script using JQuery that handles mousemove and keypress events. If the time expires, the page reload.

<script type="text/javascript">
var idleTime = 0;
$(document).ready(function () {
    //Increment the idle time counter every minute.
    var idleInterval = setInterval(timerIncrement, 60000); // 1 minute

    //Zero the idle timer on mouse movement.
    $(this).mousemove(function (e) {
        idleTime = 0;
    });
    $(this).keypress(function (e) {
        idleTime = 0;
    });
});

function timerIncrement() {
    idleTime = idleTime + 1;
    if (idleTime > 19) { // 20 minutes
        window.location.reload();
    }
}
</script>   

Answer 5

You can do it more elegantly with underscore and jquery-

$('body').on("click mousemove keyup", _.debounce(function(){
    // do preload here
}, 1200000)) // 20 minutes debounce

Answer 6

You can use the below mentioned solution

var idleTime;
$(document).ready(function () {
         reloadPage();
        $('html').bind('mousemove click mouseup mousedown keydown keypress keyup submit change mouseenter scroll resize dblclick', function () {
            clearTimeout(idleTime);
            reloadPage();
        });
});
function reloadPage() {
    clearTimeout(idleTime);
    idleTime = setTimeout(function () {
        location.reload();
    }, 3000);
}