1、首先新建一个index文件<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> </head> <body> </body></html>

3、在body里写一个按钮<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> <script type="text/javascript"> </script> </head> <body> <div id="id"></div> <button id="btn">关闭</button> </body></html>

5、获取body里div的id<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> <script type="text/javascript"> window.onload = function(){ var time = document.getElementById("id"); } </script> </head> <body> <div id="id"></div> <button id="btn">关闭</button> </body></html>

7、在这里写一个定时器<!DOCTYPE html><html>挢旗扦渌; <head> <稆糨孝汶;meta charset="UTF-8"> <title></title> <script type="text/javascript"> window.onload = function(){ var time = document.getElementById("id"); var i = 0; time = setInterval(function(){ id.innerHTML = i++;//写一个定时器,第一个参数函数中获取变量i的值 },1000);//第二个参数是它每次变动所间隔的时间,单位量为毫秒1000毫秒等于1秒 </script> </head> <body> <div id="id"></div> <button id="btn">关闭</button> </body></html>

9、最后快捷键Ctrl+R网页运行~~~一个定时器就出来啦~
