关于DOM元素
DOM独立于具体的编程语言，通常通过JavaScript访问DOM，不过并不严格要求这样。可以使用任何脚本语言来访问DOM，这要归功于其一致的API。
DOM元素的属性：
childNodes:返回当前元素所有的子元素的数组
firstChild:返回当前元素的第一个下级子元素
lastChild:返回当前元素的最后一个子元素
nextSibling:返回紧跟在当前元素后面的元素
nodeValue:指定表示元素值的读/写属性
parentNode:返回元素的父节点
previousibling:返回紧邻当前元素之前的元素
DOM元素的方法：
getElementById(id):获取指定惟一ID属性值文档中的元素
getElementsByTagName(name):返回妆前元素中有指定标记名的子元素的数组
hasChildNodes():返回一个布尔值，指示元素是否有子元素
getAttribute(name):返回元素的属性值，属性由name指定
下面是一个例子：jsp代码如下：
<head>
<script language="javascript" type="text/javascript">
var XMLrequest = false;
var requsettype;
try {
request = new XMLHttpRequest();
} catch (trymicrosoft) {
try {
XMLrequest = new ActiveXObject("Msxml2.XMLHTTP");
} catch (othermicrosoft) {
try {
XMLrequest = new ActiveXObject("Microsoft.XMLHTTP");
} catch (failed) {
XMLrequest = false;
}
}
}
if (!XMLrequest){
alert("Error initializing XMLHttpRequest!");
}
function startrequest(requestedList) {
requsettype = requestedList;
var url = "response.xml";
// Open a connection to the server
XMLrequest.open("GET", url, true);
// Setup a function for the server to run when it's done
XMLrequest.onreadystatechange = updatePage;
// Send the request
XMLrequest.send(null);
}
function updatePage() {
if (XMLrequest.readyState == 4) {
if(requsettype=="north"){
listNorthStates();
}
else if(requsettype=="all"){
listAllStates();
}
}
}
function listNorthStates(){
var xmlDoc = XMLrequest.responseXML;
var northNode = xmlDoc.getElementsByTagName("north")[0];
var out = "Northern States";
var northStates = northNode.getElementsByTagName("state");
outputList("Northern States",northStates);
}
function listAllStates(){
var xmlDoc = XMLrequest.responseXML;
var allStates = xmlDoc.getElementsByTagName("state");
outputList("All States in Document",allStates);
}
function outputList(title,states){
var out = title;
var currentState = null;
for(var i=0;i<states.length;i++){
currentState = states[i];
out = out+"\n-"+currentState.childNodes[0].nodeValue;
}
alert(out);
}
</script>
</head>
<body>
<button onClick="startrequest('all');">click me show all xml</button>
<button onClick="startrequest('north');">click me show north xml</button>
</body>
xml文件代码如下：
<?xml version="1.0" encoding="UTF-8"?>
<states>
<north>
<state>a</state>
<state>b</state>
<state>c</state>
</north>
<south>
<state>d</state>
<state>e</state>
<state>f</state>
</south>
<east>
<state>g</state>
<state>h</state>
<state>i</state>
</east>
<west>
<state>j</state>
<state>k</state>
<state>l</state>
</west>
</states>
这是我对DOM的学习，望大家给出意见
