Answers for "how to get seconds on js"

date to seconds js

var date = new Date("2015-08-25T15:35:58.000Z");
var seconds = date.getTime() / 1000; //1440516958

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);