setTimeout、setInterval第三个参数

function sum(x, y) {
	console.log(x + y);
}

setTimeout(sum, 1000, 1, 3);

定时器启动时候，第三个以后的参数是作为第一个func()的参数传进去。

var timeoutID;

function delayedAlert() {
  timeoutID = window.setTimeout(window.alert, 2*1000, 'That was really slow!');
}

function clearAlert() {
  window.clearTimeout(timeoutID);
}