DOM和数据岛结合怎么没有提取到数据？

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
"http://www.w3.org/TR/REC-html40/loose.dtd">
<HTML>
<HEAD>
<TITLE>DOM举例</TITLE>
<SCRIPT  language="JavaScript" for="window" event="onload">
title.innerText=dsoBook.XMLDocument.doucumentElement.childNodes(0).text;
author.innerText=dsoBook.XMLDocument.documentElement.childNodes(1).text;
binding.innerText=dsoBook.XMLDocument.documentElement.childNodes(2).text;
pages.innerText=dsoBook.XMLDocument.documentElement.childNodes(3).text;
price.innerText=dsoBook.XMLDocument.documentElement.childNodes(4).text;
</SCRIPT>
</HEAD>
<BODY>
<xml id="dsoBook" src="Book.xml"></xml>
<SPAN style="font-style:italic">Title:</SPAN>
<SPAN id="title" style="font-weight:bold" ></SPAN><BR><SPAN style="font-style:italic">Author:</SPAN>
<SPAN id="author" style="font-weight:bold" ></SPAN><BR><SPAN style="font-style:italic">Binding:</SPAN>
<SPAN id="binding" style="font-weight:bold" ></SPAN><BR><SPAN style="font-style:italic">Pages:</SPAN>
<SPAN id="pages" style="font-weight:bold" ></SPAN><BR><SPAN style="font-style:italic">Prices:</SPAN>
<SPAN id="price" style="font-weight:bold" ></SPAN><BR>
</BODY>
</HTML>