how to use seconds in javascript code example

Example 1: how to count seconds in javascript

var seconds = 0;
var el = document.getElementById('seconds-counter');

function incrementSeconds() {
    seconds += 1;
    el.innerText = "You have been here for " + seconds + " seconds.";
}

var cancel = setInterval(incrementSeconds, 1000);

Example 2: how to add seconds to time in js

const date = new Date('2020-01-01 10:11:55');date.setSeconds(date.getSeconds() + 10);