Browser-idle-time-check.js

var IdleTime = 0;
setTime();
$(this).on("mousemove keypress", function () {
    IdleTime = 0;
});
function setTime() {
    setTimeout(function () {
        IdleTime += 1;
        console.log(IdleTime + " Second passed.");
        checkTime();
    }, 5000);
}

function checkTime() {
    if (IdleTime <= 2)
        setTime();
    else
        console.log('Session Timeout!!!! ' + IdleTime);
        // reference ajax function here.
}

or use this plugin: https://www.paulirish.com/2009/jquery-idletimer-plugin/