digital countdown clock

digial-countdown-clock.js

var time = 1000;

function updateTimer() { 
  document.body.innerHTML = ('<div style="font-size: 6em">' + Math.round(time/60) + ":" + (--time%60) + '</div><br/><div>' + time + ' total seconds</div>') 
}

var timerId = setInterval( updateTimer, 1000)

// reset with:
// clearInterval(timerId); 

Paste this into the console and it will take over the page.