Find elapsed time in javascript

Question

I\'m new to JavaScript and I\'m trying to write a code which calculates the time elapsed from the time a user logged in to the current time.

Here is my code:-

Answer 1

There's too much going on here.

An easier way would just be to compare markDate to the current date each time and reformat.

See Demo: http://jsfiddle.net/7e4psrzu/

function markPresent() {
    window.markDate = new Date();
    $(document).ready(function() {
        $("div.absent").toggleClass("present");
    });
    updateClock();
}

function updateClock() {  
    var currDate = new Date();
    var diff = currDate - markDate;
    document.getElementById("timer").innerHTML = format(diff/1000);
    setTimeout(function() {updateClock()}, 1000);
}

function format(seconds)
{
var numhours = parseInt(Math.floor(((seconds % 31536000) % 86400) / 3600),10);
var numminutes = parseInt(Math.floor((((seconds % 31536000) % 86400) % 3600) / 60),10);
var numseconds = parseInt((((seconds % 31536000) % 86400) % 3600) % 60,10);
    return ((numhours<10) ? "0" + numhours : numhours)
    + ":" + ((numminutes<10) ? "0" + numminutes : numminutes)
    + ":" + ((numseconds<10) ? "0" + numseconds : numseconds);
}

markPresent();

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<div id="timer"></div>

Answer 2

You can simply use performance.now()

Example:

start = performance.now();

elapsedTime = performance.now() - start;

Answer 3

I would use the getTime() method, subtract the time and then convert the result into hh:mm:ss.mmm format.