XML DOM教程

XML DOM - 遍历

在本章中，我们将讨论XML DOM Traversing.我们在上一章中研究了如何加载XML文档并解析由此获得的DOM对象.可以遍历此解析的DOM对象.遍历是一个循环，通过在节点树中逐步遍历每个元素，以系统方式完成循环.

示例

以下示例(traverse_example.htm)演示了DOM遍历.在这里，我们遍历< Employee>的每个子节点.元素.

<!DOCTYPE html>
<html>
   <style>
      table,th,td {
         border:1px solid black;
         border-collapse:collapse
      }
   </style>
   <body>
      <div id = "ajax_xml"></div>
      <script>
         //if browser supports XMLHttpRequest
         if (window.XMLHttpRequest) {// Create an instance of XMLHttpRequest object. 
            code for IE7+, Firefox, Chrome, Opera, Safari
            var xmlhttp = new XMLHttpRequest();
         } else {// code for IE6, IE5
            var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
         }
         // sets and sends the request for calling "node.xml"
            xmlhttp.open("GET","https://img01.yuandaxia.cn/Content/img/tutorials/dom/node.xml",false);
            xmlhttp.send();

         // sets and returns the content as XML DOM
            var xml_dom = xmlhttp.responseXML;
	
         // this variable stores the code of the html table
            var html_tab = '<table id = "id_tabel" align = "center">
            <tr>
               <th>Employee Category</th>
               <th>FirstName</th>
               <th>LastName</th>
               <th>ContactNo</th>
               <th>Email</th>
            </tr>';
            var arr_employees = xml_dom.getElementsByTagName("Employee");
         // traverses the "arr_employees" array
            for(var i = 0; i<arr_employees.length; i++) {
               var employee_cat = arr_employees[i].getAttribute('category');
   
               // gets the value of 'category' element of current "Element" tag

               // gets the value of first child-node of 'FirstName' 
               // element of current "Employee" tag
                  var employee_firstName =
                     arr_employees[i].getElementsByTagName('FirstName')[0].childNodes[0].nodeValue;

               // gets the value of first child-node of 'LastName' 
               // element of current "Employee" tag
                  var employee_lastName =
                     arr_employees[i].getElementsByTagName('LastName')[0].childNodes[0].nodeValue;

               // gets the value of first child-node of 'ContactNo' 
               // element of current "Employee" tag
                  var employee_contactno = 
                     arr_employees[i].getElementsByTagName('ContactNo')[0].childNodes[0].nodeValue;

               // gets the value of first child-node of 'Email' 
               // element of current "Employee" tag
                  var employee_email = 
                     arr_employees[i].getElementsByTagName('Email')[0].childNodes[0].nodeValue;

               // adds the values in the html table
               html_tab += '<tr>
                  <td>'+ employee_cat+ '</td>
                  <td>'+ employee_firstName+ '</td>
                  <td>'+ employee_lastName+ '</td>
                  <td>'+ employee_contactno+ '</td>
                  <td>'+ employee_email+ '</td>
               </tr>';
            }
         html_tab += '</table>'; 
         // adds the html table in a html tag, with id = "ajax_xml"
         document.getElementById('ajax_xml').innerHTML = html_tab; 
      </script>
   </body>
</html>