求一个jsp+ajax的二级联动无刷新菜单

very good.

<tr>

				<td>

					<b>节目类型</b>

				</td>

				<td>

					<select name="bigTypeSelect" onchange="getSmallType(this.value);">

						<option value="-1">

							未选择

						</option>

						<c:forEach items="${bigTypeList}" var="temp">

							<option value="${temp.typeId}">

								${temp.typeName}

							</option>

						</c:forEach>

					</select>

					 

					<select name="typeId">

						<option value="-1">

							未选择

						</option>

					</select>

				</td>

</tr>

<script type="text/javascript">

		//创建XMLHttpRequest对象       

    	function createXMLHttpRequest() 

    	{

    		//Mozilla 浏览器

	        if(window.XMLHttpRequest) 

	        { 

	            XMLHttpReq = new XMLHttpRequest();

	        }

	        // IE浏览器

        	else if (window.ActiveXObject) 

        	{ 

	            try 

	            {

	                XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");

	            } 

	            catch (e) 

	            {

	                try 

	                {

	                    XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");

	                } 

	                catch (e) {}

	            }

	        }

    	}

		

    	//发送请求函数

		function getSmallType(bigTypeId)

		{

			if(bigTypeId == -1)

			{

				var typeId = document.forms[0].typeId;

				//清空select所有option选项

				typeId.options.length = 0;

				var option = document.createElement("option");

				option.text = "未选择";

				option.value = -1;

				typeId.options.add(option);

				return false;

			}

			

			createXMLHttpRequest();	

			XMLHttpReq.onreadystatechange = getFinsh; 

			

			var url = "getsmalltype.do?bigtypeid="+bigTypeId;

			XMLHttpReq.open("post",url , true); 

			XMLHttpReq.send(null); 

		}

		

		//处理返回响应函数

		function getFinsh()

		{ 

			if (XMLHttpReq.readyState == 4) 

			{

				if (XMLHttpReq.status == 200) 

				{ 

					if(window.ActiveXObject)

						{

							var xmlDom = new ActiveXObject("Microsoft.XMLDOM");

						}

						else

						{

							if(document.implementation && document.implementation.createDocument)

							{

								var xmlDom=document.implementation.createDocument("","doc",null);

							}

						}

						xmlDom.async = false;

						xmlDom.loadXML(XMLHttpReq.responseText);

						

						var typeId = document.forms[0].typeId;

						//清空select所有option选项

						typeId.options.length = 0;

								

						var smallTypes = xmlDom.getElementsByTagName("smalltypes/smalltype");

						//包含子类信息

						if(smallTypes.length != 0)

						{

							var option = document.createElement("option");

							option.text = "未选择";

							option.value = -1;

							typeId.options.add(option);

						

							for(var i = 0;i < smallTypes.length;i ++)

				        	{

					            //子类ID

						        var typeIdText = smallTypes[i].firstChild.text;

						        //alert(typeIdText);

						        

						       	//子类名

					            var typeNameText = smallTypes[i].lastChild.text;

					            //alert(typeNameText);

					            

					          	//添加子类信息到下拉列表

								var option = document.createElement("option");

								option.text = typeNameText;

								option.value = typeIdText;

								typeId.options.add(option);

				            }

			            }

			            else

			            {

			            	var option = document.createElement("option");

							option.text = "无子类";

							option.value = document.forms[0].bigTypeSelect.options(document.forms[0].bigTypeSelect.selectedIndex).value;

							typeId.options.add(option);

			            }

				} 

				else 

				{ 

					alert("Error data:\n"+ XMLHttpReq.statusText); 

			    } 

		    }

		 }

</script>

        //获得小类信息XML

	public String getSmallTypeByBigTypeIdXml(String configFilePath,

			String bigTypeId) {

		File file = new File(configFilePath);

		Configuration conf = new Configuration().configure(file);

		SessionFactory sessionFactory = null;

		sessionFactory = conf.buildSessionFactory();

		Session session = sessionFactory.openSession();

		Query query = session

				.createQuery("from TypeInfo where parentId = :parentid");

		query.setInteger("parentid", Integer.parseInt(bigTypeId));

		List list = query.list();

		session.close();

		StringBuffer xmlSb = new StringBuffer("<smalltypes>");

		for (int i = 0; i < list.size(); i++) {

			TypeInfo typeInfo = (TypeInfo) list.get(i);

			xmlSb.append("<smalltype><typeid>" + typeInfo.getTypeId()

					+ "</typeid><typename>" + typeInfo.getTypeName()

					+ "</typename></smalltype>");

		}

		xmlSb.append("</smalltypes>");

		return xmlSb.toString();

	}