<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="../js/jquery.min.js"></script>
<style>
.active{font-size:16px;color:#ffffff;
background: #000000;padding:10px;}
</style>
</head>
<body>
数字从1变化到10：<div id="box1">0</div>
自动添加类：<div id="box2">0000000</div>
3秒后自动添加类：<div id="box3">0000000</div>
<script>
$(function () {
fn1("#box1");
fn2("#box2"); //方法执行
setTimeout("fn2(‘#box3‘)",3000) //3秒后方法自动执行
});
function fn1(selector){
var num=0;
timer=setInterval(function(){
num++;
// alert(num)
// var text="<span>"+num+",</span>"
// $(selector).append(text); //节点添加
$(selector).text(num);
if(num==10){
clearInterval(timer); //定时器清除；
}
},1000);
};
function fn2(selector){
$(selector).addClass("active");
};
</script>
原文：https://www.cnblogs.com/0826sw/p/11915285.html