1、因为执行scrip是,下面的页面还没有加载,所以需要添加onload
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="js/jquery-1.8.3.js" ></script>
<script>
function t(){
$("#logo").attr("href","http://www.baidu.com");
}
</script>
</head>
<body onload="t()">
<a id="logo">baidu</a>
</body>
</html>
2、
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="js/jquery-1.8.3.js" ></script>
<script>
$(function(){
$("#logo").attr("href","http://www.baidu.com");
});
</script>
</head>
<body>
<a id="logo">baidu</a>
</body>
</html>
3、ready:HTML文档加载完成之后,浏览器执行fn函数,简写为$();
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="js/jquery-1.8.3.js" ></script>
<script>
$(document).ready(function(){
$("#logo").attr("href","http://www.baidu.com");
});
</script>
</head>
<body>
<a id="logo">baidu</a>
</body>
</html>