XML学习错误（1）：大小写的问题

       笔者是一个编程菜鸟，最近努力学习Ajax技术，感觉JS不太好驯服，但是本人依然不断努力。笔者认为把自己的编程错误记录下来，是对经验的积累，经验是慢慢积累的嘛。
       今天就是在学习XML DOM编程过程中，出现了一个错误，浏览器总是告诉我有一个参数无效，后来经过认真研究终于找到了。
       先把代码给大家看看吧。
 

  1 <! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
  2 < html >
  3 < head >
  4 < title ></ title >
  5 < meta  name ="GENERATOR"  content ="Microsoft Visual Studio .NET 7.1" >
  6 < meta  name ="vs_targetSchema"  content ="http://schemas.microsoft.com/intellisense/ie5" >
  7 </ head >
  8 < body  onload ="initializeBook();" >
  9    < h1 >   Wrox Press  </ h1 >
 10    < h3 >  Book Information  </ h3 >
 11    < TABLE  BORDER ="0"  CELLSPACING ="0"  CELLPADDING ="0" >
 12      < TR >
 13          < TD > Title: </ TD >< TD >< input  id ="txtTitle" ></ TD >
 14      </ TR >
 15      < TR >
 16          < TD > Publisher: </ TD >< TD >< input  id ="txtPublisher" ></ TD >
 17      </ TR >
 18      < TR >
 19          < TD > Published Date: </ TD >< TD >< input  id ="txtPubDate" ></ TD >
 20      </ TR >
 21      < TR >
 22          < TD > Abstract: </ TD >< TD >< input  id ="txtAbstract" ></ TD >
 23      </ TR >
 24      < TR >
 25          < TD > Pages </ TD >< TD >< input  id ="txtPages" ></ TD >
 26      </ TR >
 27      < TR >
 28          < TD > ISBN: </ TD >< TD >< input  id ="txtISBN" ></ TD >
 29      </ TR >
 30      < TR >
 31          < TD > Price: </ TD >< TD >< input  id ="txtPrice" ></ TD >
 32      </ TR >
 33     
 34 </ TABLE >
 35
 36     < input  type ="button"  id ="btnUpdate"  value ="Update Book Info"  onclick ="updateBookInfo();"   />
 37    
 38     < h3 > Author: </ h3 >
 39     < table >
 40       < tr >
 41          < td > Author: </ td >< td >< input  id ="txtAuthor" ></ td >
 42       </ tr >
 43     </ table >
 44     < input  type ="button"  id ="btnAddAuthor"  value ="Add Author"  onclick ="addAuthor();"   />
 45     < h3 > Catagories: </ h3 >
 46      < table >
 47       < tr >
 48          < td > Category: </ td >< td >< input  id ="txtCategory" ></ td >
 49       </ tr >
 50     </ table >
 51     < input  type ="button"  id ="btnAddCategory"  value ="Add category"  onclick ="addCategory();" />
 52    
 53      < XML  id =docBook >
 54          < Book >
 55          </ Book >
 56      </ XML >
 57     
 58    < script >
 59  var docBook;
 60  function initializeBook()
 61  {
 62    docBook=document.all("docBook").XMLDocument;
 63    docBook.async=false;
 64    renderElements();
 65  }
 66  
 67  function createOrReplaceElement(sElementName,sElementValue,elementParent)
 68  {
 69    var elementItem;
 70    var textValue;
 71    var nodelistOldItem;
 72    
 73    elementItem=docBook.createElement(sElementName);
 74    textValue=docBook.createTextNode(sElementValue);
 75    elementItem.appendChild(textValue);
 76    
 77    nodelistOldItem=elementParent.getElementsByTagName(sElementName);
 78    if (nodelistOldItem.length>0)
 79    {
 80       elementParent.replaceChild(elementItem,nodelistOldItem.item(0));
 81    }
 82    else
 83    {
 84       elementParent.appendChild(elementItem);
 85    }
 86    
 87  }
 88  
 89  function updateBookInfo()
 90  {
 91    createOrReplaceElement("Title",txtTitle.value,docBook.documentElement);
 92    createOrReplaceElement("Publisher",txtPublisher.value,docBook.documentElement);
 93    createOrReplaceElement("PubDate",txtPubDate.value,docBook.documentElement);
 94    createOrReplaceElement("Abstract",txtAbstract.value,docBook.documentElement);
 95    createOrReplaceElement("Pages",txtPages.value,docBook.documentElement);
 96    createOrReplaceElement("ISBN",txtISBN.value,docBook.documentElement);
 97    createOrReplaceElement("Price",txtPubDate.value,docBook.documentElement);
 98    
 99    renderElements();      
100  }
101  
102  function addAuthor()
103  {
104    var elementAuthor;
105    var textAuthor;
106    var nodelistAuthors;
107    var elementAuthors;
108    
109    elementAuthor=docBook.createElement("Author");
110    textAuthor=docBook.createTextNode(txtAuthor.value);
111    elementAuthor.appendChild(textAuthor);
112    nodelistAuthors=docBook.getElementsByTagName("Authors");
113    if(nodelistAuthors.length==0)
114    {
115      elementAuthors=docBook.createElement("Authors");
116      docBook.documentElement.appendChild(elementAuthors);
117    }
118    else
119    {
120      elementAuthors=nodelistAuthors.item(0);
121    }
122    elementAuthors.appendChild(elementAuthor);
123    renderElements();
124  }
125  
126  function addCategory()
127  {
128    var elementCategory;
129    var textCategory;
130    var nodelistRecSubjCategories;
131    var elementRecSubjCategories;
132    
133    elementCategory=docBook.createElement("Category");
134    textCategory=docBook.createTextNode(txtCategory.value);
135    elementCategory.appendChild(textCategory);
136    nodelistRecSubjCategories=docBook.getElementsByTagName("RecSubjCategories");
137    
138    if(nodelistRecSubjCategories.length==0)
139    {
140       elementRecSubjCategories=docBook.createElement("RecSubjCategories");
141       docBook.documentElement.appendChild(elementRecSubjCategories);
142    }  
143    else
144    {
145       elementRecSubjCategories=nodelistRecSubjCategories.item(0);
146    }
147    
148    elementRecSubjCategories.appendChild(elementCategory);
149    
150    renderElements();
151  }
152  
153  function renderElements()
154  {
155    document.all("divRawXML").innerText=docBook.xml;
156    bookInfo.innerHTML=docBook.transformNode(bookXSL.documentElement);
157    authorTable.innerHTML=docBook.transformNode(authorXSL.documentElement);
158    categoryTable.innerHTML=docBook.transformNode(categoryXSL.documentElement);
159    
160  }
161  
162  
163 </ script >
164
165
166      < XML  id =bookXSL >
167       < DIV  xmlns:xsl ="http://www.w3.org/TR/wd-xsl" >
168         < xsl:choose >
169           < xsl:when  test ="/Book/Title[. $ne$ '']" >
170             < table  border ="0"  cellpadding ="1" >
171               < tr >
172                 < td > Title: </ td >< td >< xsl:value-of  select ="/Book/Title" /></ td >
173               </ tr >
174               < tr >
175                 < td > Publisher: </ td >< td >< xsl:value-of  select ="/Book/Publisher" /></ td >
176               </ tr >
177               < tr >
178                 < td > Published Date: </ td >< td >< xsl:value-of  select ="/Book/PubDate" /></ td >
179               </ tr >
180               < tr >
181                 < td > Abstract: </ td >< td >< xsl:value-of  select ="/Book/Abstract" /></ td >
182               </ tr >
183               < tr >
184                 < td > Pages: </ td >< td >< xsl:value-of  select ="/Book/Pages" /></ td >
185               </ tr >
186               < tr >
187                 < td > ISBN: </ td >< td >< xsl:value-of  select ="/Book/ISBN" /></ td >
188               </ tr >
189                < tr >
190                 < td > Price: </ td >< td >< xsl:value-of  select ="/Book/Price" /></ td >
191               </ tr >
192             </ table >
193           </ xsl:when >
194           < xsl:otherwise >
195            Book Information not yet specified.
196           </ xsl:otherwise >
197         </ xsl:choose >
198       </ DIV >
199       
200      </ XML >
201     
202      < XML  id =authorXSL >
203         < DIV  xmlns:xsl ="http://www.w3.org/TR/wd-xsl" >
204          < table  border ="0"  cellpadding ="1" >
205            < tr >
206              < td >< strong > Authors </ strong ></ td >
207            </ tr >
208            < xsl:for-each  select ="/Book/Authors/Author" >
209             < tr >
210               < td >< xsl:value-of  select ="text()"   /></ td >
211             </ tr >
212            </ xsl:for-each >
213           </ table >
214         </ DIV >
215      </ XML >
216     
217      < XML  id =categoryXSL >
218        < DIV  xmlns:xsl ="http://www.w3.org/TR/wd-xsl" >
219          < table  border ="0"  cellpadding ="1" >
220            < tr >
221              < td >< strong > Categories </ strong ></ td >
222            </ tr >
223            < xsl:for-each  select ="/Book/RecSubjCategories/Category" >
224               < tr >
225                 < td >< xsl:value-of  select ="text()"   /></ td >
226               </ tr >
227            </ xsl:for-each >
228          </ table >
229        </ DIV >
230      </ XML >
231     
232      < hr  />
233      < h2 > Book Information </ h2 >
234      < div  id ="bookInfo" ></ div >
235      < div  id ="authorTable" ></ div >
236      < div  id ="categoryTable" ></ div >
237      < hr />
238     The Text expression of the current contents of the DOM tree is:
239     < DIV  id ="divRawXML" ></ DIV >
240   
241
242 </ body >
243 </ html >
244
245

出现问题的代码是这一行：
   

1 function  renderElements()
2    {
3    document.all("divRawXML").innerText=docBook.xml;
4    bookInfo.innerHTML=docBook.transformNode(bookXSL.documentElement);
5    authorTable.innerHTML=docBook.transformNode(authorXSL.documentElement);
6    categoryTable.innerHTML=docBook.transformNode(categoryXSL.documentElement);//出现问题的代码
7    
8  }

      可见，是categoryXSL.documentElement这个参数出了问题，也就是XSL出了问题，但是笔者查了半天也没搞明白，最后终于找到了代码的问题，原来出现错误的代码是这样的：
     

 1    < XML  id =categoryXSL>
 2         <DIV xmlns:xsl ="http://www.w3.org/TR/wd-xsl" >
 3           < table  border ="0"  cellpadding ="1" >
 4             < tr >
 5               < td >< strong > Categories </ strong ></ td >
 6             </ tr >
 7             < xsl:for-each  select ="/Book/RecSubjCategories/Category" >
 8                < tr >
 9                  < td >< xsl:value-of  select ="text()"   /></ td >
10                </ tr >
11             </ xsl:for-each >
12           </ table >
13         </ div > <!--  这行出了问题  -->
14       </ XML >

     出问题的原因是，由于上面的<DIV xmlns:xsl="http://www.w3.org/TR/wd-xsl">是大写的，而结尾确是小写，自然会有问题，所以把</div>改为</DIV>就可以了，即：

  < XML  id =categoryXSL>
       <DIV xmlns:xsl ="http://www.w3.org/TR/wd-xsl" >
         < table  border ="0"  cellpadding ="1" >
           < tr >
             < td >< strong > Categories </ strong ></ td >
           </ tr >
           < xsl:for-each  select ="/Book/RecSubjCategories/Category" >
              < tr >
                < td >< xsl:value-of  select ="text()"   /></ td >
              </ tr >
           </ xsl:for-each >
         </ table >
       </ DIV >
     </ XML >