window.opener 是window.open或超链接<a> 打开的子页面调用父页面对象 
例子如下 
a.html 



复制代码代码如下:


<html>  
  
<head>  
  
<title>父页面</title>  
  
<script type="text/javascript">  
  
function openB()  
  
{  
  
window.open('b.html','b','width=400,height=200,status=no,toolbar=no,menubar=no,location=no,resizable=yes,left=200,top=100');  
  
}  
  
</script>  
  
</head>  
  
<body>  
  
<form id="form1" action="">  
  
<div>  
  
输入值:  
  
<input type="text" name="username" id="username" /><br />  
  
<input type="button" value="打开窗口B" οnclick="openB();" /><br />  
  
<a href="b.html" target="_blank">超链接打开B页面</a>  
  
</div>  
  
</form>  
  
</body>  
  
</html>


b.html 



复制代码代码如下:




<html>  
  
<head>  
  
<script type="text/javascript">  
  
function getpValue()  
  
{  
  
document.getElementByIdx_x_x_x("span1").innerText=window.opener.document.getElementByIdx_x_x_x("username").value;  
  
}  
  
</script>  
  
</head>  
  
<body>  
  
<span>文本框值为:</span><span id="span1"></span><br />  
  
<input type="button" value="获取父窗口内的文本框值" οnclick="getpValue();">  
  
</body>  
  
</html>