xpath操作

XPath：xml pathLanguage，是用于确定xml某个节点位置的语言。
根据xpath查找节点的JavaScript方法

function selectSingleNode(xmldoc,sXpath){

 if (window.ActiveXObject){
      //IE浏览器
      returnxmldoc.selectSingleNode(sXpath);
  } else if(window.XPathEvaluator) {
      //FireFox类浏览器
      varxpathObj = new XPathEvaluator();
      if(xpathObj) {
          varresult =xpathObj.uate(sXpath,xmldoc,null,XPathResult.FIRST_ORDERED_NODE_TYPE,null);
          returnresult.singleNodeValue;
      }else {
          returnnull;
      }
  } else {
      returnnull;
  }
}


function selectNodes(xmldoc,sXpath){
  if (window.ActiveXObject){
      //IE浏览器
      returnxmldoc.selectNodes(sXpath);
  } else if(window.XPathEvaluator) {
      //FireFox类浏览器
      varxpathObj = new XPathEvaluator();
      if(xpathObj) {
          varresult =xpathObj.uate(sXpath,xmldoc,null,XPathResult.ORDERED_NODE_ITERATOR_TYPE,null);
          //得到的result是个迭代对象，需要把它里面的内容转存到数组中
          varnodes = new Array();
          varnode;
          while((node= result.iterateNext()) != null) {
              //把迭代器中的内容存到数组中
              nodes.push(node);
          }
          returnnodes;
      }else {
          returnnull;
      }
  } else {
      returnnull;
  }
}
下面是利用上面的方法查找xml文档中指定条件节点的代码
function testxpath(){
            varrootElement  =loadXML(true,"XPATH.xml");
            removeBlank(rootElement);
            
            //查找所有的author元素节点
            //关键就是如何表式元素节点在DOM树中的路径
            //绝对路径 /books/book/author
            //相对路径 book/author
            //全文档搜索法 //author  //book/author
            varauthor1 = selectNodes(rootElement,"/books/book/author");
            varauthor2 = selectNodes(rootElement,"book/author");
            varauthor3 = selectNodes(rootElement,"//author");
            varauthor4 = selectNodes(rootElement,"//book/author");
            
            //查找属性节点，查找book节点下isdn属性
            //关键是先找到包含属性节点的元素节点
            varisdn1 = selectNodes(rootElement,"/books/book/@isdn");
            varisdn2 =selectNodes(rootElement,"[email=book/@isdn]book/@isdn[/email]");
            varisdn3 = selectNodes(rootElement,"//book/@isdn");
            varisdn4 = selectNodes(rootElement,"//books/book/@isdn");
            
            //查找文本节点，name元素下面的文本
            //关键是找到包含文本节点的那个元素节点
            vartext1 = selectNodes(rootElement,"/books/book/name/text()");
            vartext2 = selectNodes(rootElement,"book/name/text()");
            vartext3 = selectNodes(rootElement,"//book/name/text()");
            vartext4 = selectNodes(rootElement,"//name/text()");
            
            
            //有条件的查找元素节点，包含属性isdn
            //需要首先找到元素节点，然后再增加条件表达式
            varbook1 = selectNodes(rootElement,"/books/book[@isdn]");
            varbook2 = selectNodes(rootElement,"book[@isdn]");
            varbook3 = selectNodes(rootElement,"//book[@isdn]");
            
            //多个条件与关系的查找元素节点
            //需要首先找到元素节点，然后每一个查询条件写在一个中括号中
      varbookA1 =selectNodes(rootElement,"/books/book[@isdn='0002'][price>35]");
      varbookA2 =selectNodes(rootElement,"book[@isdn='0002'][price>35]");
      varbookA3 =selectNodes(rootElement,"//book[@isdn='0002'][price>35]");
            
//多个条件或关系的查找元素节点
//需要首先找到元素节点，然后每一个查询条件写在一个XPATH的表达式，这些表达式用|组合，表式或关系
var bookO1 = selectNodes(rootElement,"/books/book[@isdn='0002'] |/books/book[price>35]");

var bookO2 = selectNodes(rootElement,"book[@isdn='0002'] |/books/book[price>35]");

var bookO3 = selectNodes(rootElement,"//book[@isdn='0002'] |/books/book[price>35]");
}