Question

What is the simplest way to increase a variable by 1 every second?

Answer 1

var counter = 0;
setInterval(function () {
  ++counter;
}, 1000);

Additionally, if you ever need to turn it off again, this makes that possible:

var counter = 0;
var myInterval = setInterval(function () {
  ++counter;
}, 1000);

// to stop the counter
clearInterval(myInterval);