provision to check if webviewer is idle for an hour

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rakesh mishra

Mar 12, 2021, 6:27:19 PM3/12/21
to PDFTron WebViewer

We are into a scenario where we need to check if user is inactive for an hour (i.e. WebViewer window/screen is idle). Is there any event or api available to check that, I couldn't find in the documentation.
If there is any way, please do let me know.


Oscar Zhang

Mar 16, 2021, 9:55:15 PM3/16/21
to PDFTron WebViewer
Hey Rakesh,

Unfortunately, we don't have an API to check user's activities, but I believe this is something you can implement with pure JavaScript, for example:

).then(async (instance) => {
  function activityWatcher(){

    //The number of seconds that have passed since the user was active.
    let secondsSinceLastActivity = 0;

    //Max Inactivity time, for example: 3 seconds.
    const maxInactivity = 3;

    //An array of DOM events that should be interpreted as user activity.
    const activityEvents = [
      'mousedown', 'mousemove', 'keydown',
      'scroll', 'touchstart'

    //Setup the setInterval method to run
    //every second. 1000 milliseconds = 1 second.
        console.log(secondsSinceLastActivity + ' seconds since the user was last active');
        //if the user has been inactive or idle for longer
        //then the seconds specified in maxInactivity
        if(secondsSinceLastActivity > maxInactivity){
            console.log('User has been inactive for more than ' + maxInactivity + ' seconds');
    }, 1000);

    //The function that will be called whenever a user is active
    function activity(){
        //reset the secondsSinceLastActivity variable
        //back to 0
        secondsSinceLastActivity = 0;

    activityEvents.forEach(function(eventName) {
      //add these events to the webviewer iframe
      const viewerWindow = document.getElementById('viewer').querySelector('iframe').contentWindow;
      //register the activity function as the listener parameter.
      viewerWindow.document.body.addEventListener(eventName, activity, true);



The code above is from, I modified it a little bit to make it works in WebViewer, but there are also many other posts/tutorials that you may find useful:

Best Regards,
Oscar Zhang
Software Developer
PDFTron Systems, Inc.

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