怎样得到这个子窗口中的值呀？(ShowModalDialog窗口)

parentfrm.html

 1<html>
 2<head>
 3<title>父窗口</title>
 4<script language="javascript">   
 5<!--   
 6var wName;   
 7function fnOpen()   
 8{   
 9wName=window.showModalDialog("frmChild.html",sendFromParent.value);   
10}   
11//-->   
12</script>
13</head>
14<body>   
15请输入要传递给子窗口的数据信息<input name="sendFromParent" type="text"/><input name="btnSendMsg" onclick="fnOpen();" type="button" value="发送"/>
16<br/>   
17从子窗口传递给父窗口的数据为：<input name="getFromChildMsg" type="text"/>
18<div id="oDiv"></div>
19</body>
20</html>

childfrm.html

 1<html>
 2<head>
 3<title>子窗口</title>
 4<script language="javascript">   
 5<!--   
 6var getFromParent=window.dialogArguments;   
 7var showGetMsg="接收到父窗口的信息为:" + getFromParent;   
 8document.write(showGetMsg);   
 9  
10function sendFromChild()   
11{   
12opener.oDiv.innerText=txtSendFromChildMsg.value;   
13}   
14//-->   
15</script>
16</head>
17<body>
18<br/>   
19子窗口传递给父窗口的数据为:<input name="txtSendFromChildMsg" type="text"/><input onclick="sendFromChild();" type="button" value="发送"/>
20</body>
21</html>

为什么opener.oDiv.innerText=txtSendFromChildMsg.value;这句话报错呢？有什么办法能得到吗？

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showModalDialoｌ打开的窗口本身就不是跟打开它的窗口是父子关系吧
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==========================================================

 1<html>
 2<head>
 3<title>父窗口</title>
 4<script language="javascript">   
 5<!--   
 6var wName;   
 7function fnOpen()   
 8{   
 9wName=window.open("childfrm.html?"+sendFromParent.value);   
10}   
11//-->   
12</script>
13</head>
14<body>   
15请输入要传递给子窗口的数据信息<input id="sendFromParent" type="text"/><input name="btnSendMsg" onclick="fnOpen();" type="button" value="发送"/>
16<br/>   
17从子窗口传递给父窗口的数据为：<input id="getFromChildMsg" type="text"/>
18<div id="oDiv"></div>
19</body>
20</html>

============================================================

 1<html>
 2<head>
 3<title>子窗口</title>
 4<script language="javascript">   
 5<!--   
 6var getFromParent=location.search;   
 7var showGetMsg="接收到父窗口的信息为:" + getFromParent;   
 8document.write(showGetMsg);   
 9  
10function sendFromChild()   
11{   
12opener.getFromChildMsg.value=txtSendFromChildMsg.value   
13}   
14//-->   
15</script>
16</head>
17<body>
18<br/>   
19子窗口传递给父窗口的数据为:<input name="txtSendFromChildMsg" type="text"/><input onclick="sendFromChild();" type="button" value="发送"/>
20</body>
21</html>

---------------------------------------------------------------

function fnOpen()
{
oDiv.innerText=window.showModalDialog("frmChild.html",sendFromParent.value);
}

2.
function sendFromChild()
{
window.returnValue=txtSendFromChildMsg.value;
window.close();
}

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测试通过
frmParent.html

 1<html>
 2<head>
 3<title>父窗口</title>
 4<script language="javascript">   
 5<!--   
 6var wName;   
 7function fnOpen()   
 8{   
 9wName=window.showModalDialog("frmChild.html",sendFromParent.value);   
10alert(wName);   
11oDiv.innerText=wName;   
12}   
13//-->   
14</script>
15</head>
16<body>   
17请输入要传递给子窗口的数据信息<input name="sendFromParent" type="text"/><input name="btnSendMsg" onclick="fnOpen();" type="button" value="发送"/>
18<br/>   
19从子窗口传递给父窗口的数据为：<input name="getFromChildMsg" type="text"/>
20<span id="oDiv">asdf</span>
21</body>
22</html>

frmChild.htm

 1<html>
 2<head>
 3<title>子窗口</title>
 4<script language="javascript">   
 5<!--   
 6var getFromParent=window.dialogArguments;   
 7var showGetMsg="接收到父窗口的信息为:" + getFromParent;   
 8document.write(showGetMsg);   
 9  
10function sendFromChild()   
11{ alert(txtSendFromChildMsg.value);   
12window.returnValue =txtSendFromChildMsg.value;   
13window.close();   
14}   
15//-->   
16</script>
17</head>
18<body>
19<br/>   
20子窗口传递给父窗口的数据为:<input name="txtSendFromChildMsg" type="text"/><input onclick="sendFromChild();" type="button" value="发送"/>
21</body>
22</html>