1、首先新建一个index文件
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
</body>
</html>
2、在head里写写个script标签
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
</script>
</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>
4、在script标签里写
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
window.onload = function(){
}
</script>
</head>
<body>
<div id="id"></div>
<button id="btn">关闭</button>
</body>
</html>
让它先加载网页再加载js模块
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>
6、声明一个变量
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
window.onload = function(){
var time = document.getElementById("id");
var i = 0;
}
</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>
<head>
<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>
8、再写一个定时器关闭的函数
<!DOCTYPE html>
<html>
<head>
<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
var button = document.getElementById("btn");//获取按钮id
button.onclick = function(){
clearTimeout(time);//点击按钮关闭定时器
}
}
</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~
