如何在JavaScript中制作计时器？

Question

I want reverse timer for session time out. I got one code on codepen. This code is clockwise timer , I tried to make it anti-clock wise , I am failed. Please suggest me. I want to make 1 hour or 59min 59sec time out. Please help me Here is the codepen demo.

if((intervalCounter%1000)==0){
                currentTime += 1000;
                var appendHour = currentTime / (1000 * 60 * 60) | 0; 
                var appendMinute = currentTime % (1000 * 60 * 60) / (1000 * 60) | 0;
                var appendSecond = currentTime  % (1000 * 60) / 1000 | 0;

                appendHour = appendHour < 10 ? "0" + appendHour : appendHour;
                appendMinute = appendMinute < 10 ? "0" + appendMinute : appendMinute;
                appendSecond = appendSecond < 10 ? "0" + appendSecond : appendSecond;
                hour.html(appendHour);
                min.html(appendMinute);
                sec.html(appendSecond);

                }

Answer 1

This code is work for anti-clockwise direction.I hope you get some idea from below example.

 // Set the date we're counting down to var countDownDate = new Date("July 5, 2019 15:37:25").getTime(); // Update the count down every 1 second var x = setInterval(function() { // Get today's date and time var now = new Date().getTime(); // Find the distance between now and the count down date var distance = countDownDate - now; // Time calculations for days, hours, minutes and seconds var days = Math.floor(distance / (1000 * 60 * 60 * 24)); var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60)); var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60)); var seconds = Math.floor((distance % (1000 * 60)) / 1000); // Output the result in an element with id="demo" document.getElementById("demo").innerHTML = days + "d " + hours + "h " + minutes + "m " + seconds + "s "; // If the count down is over, write some text if (distance < 0) { clearInterval(x); document.getElementById("demo").innerHTML = "EXPIRED"; } }, 1000); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <p id="demo"></p>