javascript create timer code example

Example 1: javascript count time

// The getTime() method returns the number of milliseconds since midnight of January 1, 1970.


var start = new Date().getTime();

for (i = 0; i < 50000; ++i) {
// do something
}

var end = new Date().getTime();
var time = end - start;
alert('Execution time: ' + time);

Example 2: timer in javascript

//single event i.e. alarm, time in milliseconds
var timeout = setTimeout(function(){yourFunction()},10000);
//repeated events, gap in milliseconds
var interval = setInterval(function(){yourFunction()},1000);

Example 3: javascript countdown timer including days

var countDownDate = new Date("Jul 25, 2021 16:37:52").getTime();

var myfunc = setInterval(function() {
    var now = new Date().getTime();
    var timeleft = countDownDate - now;
        
    var days = Math.floor(timeleft / (1000 * 60 * 60 * 24));
    var hours = Math.floor((timeleft % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
    var minutes = Math.floor((timeleft % (1000 * 60 * 60)) / (1000 * 60));
    var seconds = Math.floor((timeleft % (1000 * 60)) / 1000);
    
    }, 1000)