Page: validation.html
<%@ page contenttype= "text/html; CHARSET=GBK "%>
<title>
Using Ajax for validation
</title>
<script type= "Text/javascript" >
XMLHttpRequest objects
var xmlHttp;
Creating XMLHttpRequest Objects
function Createxmlhttprequest () {
if (window. ActiveXObject) {
XmlHttp = new ActiveXObject ("Microsoft.XMLHTTP");
}
else if (window. XMLHttpRequest) {
XmlHttp = new XMLHttpRequest ();
}
}
Validation method
function Validate () {
Creating objects
Createxmlhttprequest ();
Get Form Date value
var date = document.getElementById ("birthdate");
Submit Address
var url = "validationservlet?birthdate=" + Escape (Date.Value);
Xmlhttp.open ("Get", url,true);
Xmlhttp.onreadystatechange=callback;
Xmlhttp.send (NULL);
}
//callback methods
function Callback () {
if ( Xmlhttp.readystate = = 4) {
if (xmlhttp.status {
var mes = XmlHttp.responseXML.getElementsByTagName ("message") [0].firstchild.data;
var val = XmlHttp.responseXML.getElementsByTagName ("passed") [0].firstchild.data;
//Set hint information
setmessage (Mes,val);
}
}
}
Set up a hint information
function Setmessage (message,isvalid) {
var Messagearea = document.getElementById ("Datemessage");
var fontcolor = "Red";
if (IsValid = = "true") {
FontColor = "green";
}
Messagearea.innerhtml= "<font color=" + fontcolor + ">" + message + "</font>";
}
</script>
<body>
Ajax Validation Example
Birth date:<input type= "text" size= "ten" id= "Birthdate"/>
<div id= "Datemessage" ></div>
</body>
Server-side code, performing validation
Validationservlet.java
Import javax.servlet.*;
Import javax.servlet.http.*;
Import java.io.*;
Import java.util.*;
Import Java.text.SimpleDateFormat;
public class Validationservlet extends HttpServlet {
private static final String Content_Type = "text/html;" CHARSET=GBK ";
Initialize Global Variables
public void Init () throws Servletexception {
}
/**
* Process GET Requests
* @param request HttpServletRequest
* @param response HttpServletResponse
* @throws servletexception
* @throws IOException
*/
public void doget (HttpServletRequest request, httpservletresponse response) throws Servletexception, IOException {
Response.setcontenttype (Content_Type);
Get Output Object
PrintWriter out = Response.getwriter ();
Get the date value as a parameter validation
Boolean passed = Validatedate (Request.getparameter ("birthdate"));
Response.setcontenttype ("Text/xml");
Response.setheader ("Cache-control", "No-cache");
String message = "Your have entered an invalid date.";
if (passed) {
Message = ' You have entered a valid date. '
}
Enter XML format string
Out.println ("<response>");
Out.println ("<passed>" + boolean.tostring (passed) + "</passed>");
Out.println ("<message>" + message + "</message>");
Out.println ("</response>");
Out.close ();
}
Clean up resources
public void Destroy () {
}
/**
* Date of verification
* @param date String
* @return Boolean
*/
Private Boolean validatedate (String date) {
Boolean isValid = true;
if (date!= null) {
SimpleDateFormat formatter = new SimpleDateFormat ("mm/dd/yyyy");
try {
Formatter.parse (date);
}
catch (Exception ex) {
System.out.println (Ex.tostring ());
IsValid = false;
}
}
else{
IsValid = false;
}
return isValid;
}
}
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