​x
 
<html>
<head>
<script type="text/javascript">
function getElements()
  {
  var x=document.getElementsByName("myInput");
  alert(x.length);
  }
</script>
</head>
​
<body>
<input name="myInput" type="text" size="20" /><br />
<input name="myInput" type="text" size="20" /><br />
<input name="myInput" type="text" size="20" /><br />
<br />
<input type="button" onclick="getElements()" value="名为 'myInput' 的元素有多少个？" />
</body>
​
</html>
​