<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JavaScript获取页面上某个元素的方法 </title>
<script type="text/javascript">
function doGetElementsByTagName(){
var x=document.getElementsByTagName("input");
alert(x.length);
}
function doGetElementsByName(){
var x=document.getElementsByName("myInput");
alert(x.length);
}
function getValue(){
var x=document.getElementById("myHeader");
alert(x.innerHTML);
}
</script>
</head>
<body>
<h1 id="myHeader" onclick="getValue();">这里是头部</h1>
<p>点击头部弹出myHeader的内容</p>
<input type="text" name="myInput" size="20" />
<br />
<br />
<input type="text" name="myInput" size="20" />
<br />
<br />
<input type="text" name="myInput" size="20" />
<br />
<br />
<input type="button" onclick="doGetElementsByTagName();" value="有多少个input元素？"/>
<br />
<input type="button" onclick="doGetElementsByName();" value="有多少个name的值为myInput？"/>
</body>
</html>