<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
<body>
<p id="intro">我的课程</p>
<ul>
<li title="JS">JavaScript</li>
<li title="JQ">JQuery</li>
<li title="">HTML/CSS</li>
<li title="JAVA">JAVA</li>
<li title="">PHP</li>
</ul>
<h1>以下为li列表title的值,当title为空时,新设置值为"WEB前端技术":</h1>
<script type="text/javascript">
var lst=document.getElementsByTagName("li");
for(var i=0;i<lst.length;i++){
var txt=lst[i].getAttribute("title");
if(txt==""){
lst[i].setAttribute("title","WEB前端技术");
}else{
document.write(lst[i].getAttribute("title")+"<br />");
}
//打印一下就知道了
//document.write(lst[i].getAttribute("title")+"<br />");
}
</script>
</body>
</html>
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
<body>
<p id="intro">我的课程</p>
<ul>
<li title="JS">JavaScript</li>
<li title="JQ">JQuery</li>
<li title="">HTML/CSS</li>
<li title="JAVA">JAVA</li>
<li title="">PHP</li>
</ul>
<h1>以下为li列表title的值,当title为空时,新设置值为"WEB前端技术":</h1>
<script type="text/javascript">
var lst=document.getElementsByTagName("li");
for(var i=0;i<lst.length;i++){
var txt=lst[i].getAttribute("title");
if(txt==""){
lst[i].setAttribute("title","WEB前端技术");
}else{
document.write(lst[i].getAttribute("title")+"<br />");
}
//打印一下就知道了
//document.write(lst[i].getAttribute("title")+"<br />");
}
</script>
</body>
</html>