object对象的值怎么取？

我做了一个html在线的编辑器，其中有了object对象
可是在我取object对象的值时，却总是读不出来
代码如下：


<HTML><HEAD><TITLE>HTML在线编辑器</TITLE>
<META content="text/html; charset=gb2312" http-equiv=Content-Type>
<META content="MSHTML 5.00.3103.1000" name=GENERATOR></HEAD>

<script language="javascript">
<!--
function CheckForm()
{
alert(document.all.doc_html.value) //总是显示为undefined

document.all.content.value=document.all.doc_html.value;

}
-->
</script>

<BODY bgColor=#b1aba4 id=all text=#000000>

<form method="post" action="" onsubmit="CheckForm()" name="form1">
<TABLE border=0 cellPadding=8 width="100%">
<TBODY>
<TR>
<TD>
<object id="doc_html" name= "doc_html" data="edit.htm" width=530 height="320" type=text/x-scriptlet VIEWASTEXT></object>
<textarea name="content" style="display:none" id="content"></textarea>
</TD>
</TR>
<TR>
<TD align="center"><input name="content1" ><input type="submit" value="确 定">        <input type="reset" value="取 消">
</TD>
</TR>
</TBODY>
</TABLE>
</form>


</BODY></HTML>