JavaScript基于setTimeout实现计数的方法

var count = 0;
var timer;
var timerOn = false;
function timedCount() {
 count++;
 timer = setTimeout(function(){
  timedCount()
 }, 1000);
}
function doTimer() {
 if (!timerOn) {
  timerOn = true;
  timedCount();
 }
}
function stopCount() {
 clearTimeout(timer);
 timerOn = false;
}