本章探讨XML DOM遍历。我们在前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。遍历是通过在节点树中逐步遍历每个元素，以系统的方式进行循环的过程。
示例
以下示例（traverse_example.htm）演示DOM遍历。这里我们遍历<Employee>元素的每个childNode。
<!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","/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>
此代码加载node.xml。
接下来，将XML内容转换为JavaScript XML DOM对象。
接下来，获取使用方法getElementsByTagName（）的元素数组（带有标签元素）。
接下来，我们遍历这个数组，并在表中显示childNode值。
执行
在服务器路径上将此文件另存为traverse_example.html（此文件和node.xml应位于服务器中相同的路径上）。将显示如下输出：
