<script type="text/javascript">
function second_count(){
var num=document.getElementById("id").innerHtml;
num=num-1;
if(num>=0){
setTimeout("second_count()",1000);
document.getElementById("id").innerHtml=num;
}else {
window.open("http://www.imooc.com")
}
}
second_count();
function backFn(){
window.history.back();
}
</script>
<!DOCTYPE html>
<html>
<head>
<title>浏览器对象</title>
<meta http-equiv="Content-Type" content="text/html; charset=gkb"/>
</head>
<body>
<!--先编写好网页布局-->
<h2>操作成功</h2>
<p><span id="id">5</span>秒后回到主页<a href="" onclick="backFn()">返回</a></p>
<script type="text/javascript">
var num =document.getElementById("id").innerHTML;
function second_count(){
num=num-1;
document.getElementById("id").innerHTML=num;
if(num＝=0){
}
}
setInterval("second_count()",1000);
</script>
</body>
</html>修改了一下
1.setInterval("second_count()",1000);要放在函数外，放在函数内就无法调用自身
2.innerHTML后面的HTML是大写的