Ajax

开发平台：
Java

							<%@ page language="java" pageEncoding="GB18030"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%> 
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
 
<html> 
<head>
<title>register</title>
<script type='text/javascript'  src='<%=request.getContextPath()%>/dwr/engine.js'> </script>
  <script type='text/javascript' src='<%=request.getContextPath()%>/dwr/util.js'> </script>
  <script type='text/javascript' src='<%=request.getContextPath()%>/dwr/interface/myuserDAO.js'> </script>
  <script type='text/javascript' src='<%=request.getContextPath()%>/dwr/interface/myuser.js'> </script>
  <!-- 在dwr.xml中定义了名为Demo的JavaScript -->
  
<script type="text/javascript">   
	function checkPassword()
	{
  		var name = dwr.util.getValue("userName");
  		var word = dwr.util.getValue("password");
  		myuser = {userName:name,password:word};
  		myuserDAO.checkRegisterPassword
  		(myuser,
  			function(data)
  			{
				if(data=="密码有效，请提交")
				{
					document.registerForm.submit.focus();
				}
				else
				{
					document.registerForm.password.value="";
					document.registerForm.password.focus();
				}	
				dwr.util.setValue("passwordMessage",data);		
  			}
  		);
  		
	}
	
	function checkUserName()
	{
		var name = dwr.util.getValue("userName");
		myuser = {userName:name};
		myuserDAO.checkRegisterName
		(myuser,
			function(data)
			{
				if(data=="用户名有效")
				{
					document.registerForm.password.focus();
				}
				else				
				{
					document.registerForm.userName.value="";
					document.registerForm.userName.focus();
				}
				dwr.util.setValue("nameMessage",data);
			}
		);
	}
  /* DWR是异步的，所以浏览器不会因为我们等待在后台的HTTP请求返回而阻塞在那里。所以我们要指定一个callback函数，在请求返回的时候自动调用。这里的function(data)就是这个callback函数*/
  /* dwr.util提供了一些如getValue和setValue的函数方便我们操作页面元素 */
  </script>
  </head>
	<body>
		<html:form action="/register.do" method="post">
			userName  : 
			<html:text property="userName"/>
			<span id="nameMessage" style="width:200px ; height:10px;"></span><br/>
		<br><br>	
		    password  :
		    <html:password property="password" onfocus="checkUserName();"/><span id="passwordMessage" style="width:200px ; height:10px;"></span><br/>
			<html:submit property="submit" onfocus="checkPassword();"/><html:cancel/>
		</html:form>
	</body>
</html>

						