Today research Ajax, as follows:
Ajax Get:
Front desk:
<! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "HTTP://WWW.W3.ORG/TR/HTML4/LOOSE.DTD" >
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 ">
<title> User Registration </title>
<script type= "Text/javascript" >
var xmlhttp;
function Createxmlhttp ()
{
if (window. XMLHttpRequest)
{
Xmlhttp=new XMLHttpRequest ();
}else
{
Xmlhttp=new ActiveXObject ("Microsoft.XMLHTTP");
}
}
function CheckName ()
{
Createxmlhttp ();
var Name=document.getelementbyid ("name"). Value;
Xmlhttp.open ("GET", "Ajax/checkname?name=" +encodeuri (encodeURI (name)));//Open link
Xmlhttp.send ();//Send Request
xmlhttp.onreadystatechange=callback;//This function is called when a change in state occurs during a request
}
function callback ()
{
if (xmlhttp.readystate==4&&xmlhttp.status==200)
{
var re=xmlhttp.responsetext;//information returned by the server
if ("1" ==re)
{
Can register
var Show=document.getelementbyid ("Id_name"). Innerhtml= "<font color= ' green ' > Congratulations, you can register! </font> ";
}else
{
Can not register
var Show=document.getelementbyid ("Id_name"). Innerhtml= "<font color= ' red ' > Sorry, you can't register! </font> ";
}
}
}
</script>
<body>
<center>
<ul>
<li> Username: <input type= "text" name= "name" id= "name" onblur= "CheckName ();" ><span id= "Id_name" ></span></li>
<li> Password: <input type= "password" name= "pwd" id= "pwd" ><span id= "Id_pwd" ></span></li>
</ul>
</center>
</body>
Background:
Package Com.sp.ajax;
Import java.io.IOException;
Import Java.io.PrintWriter;
Import Java.net.URLDecoder;
Import javax.servlet.ServletException;
Import Javax.servlet.annotation.WebServlet;
Import Javax.servlet.http.HttpServlet;
Import javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
@WebServlet ("/ajax/checkname")
public class Checknameserv extends HttpServlet {
private static final Long serialversionuid = 1L;
protected void doget (HttpServletRequest req, HttpServletResponse resp) throws Servletexception, IOException { Br>req.setcharacterencoding ("GBK");
Resp.setcontenttype ("TEXT/HTML;CHARSET=GBK");
String name=req.getparameter ("name");
System.out.println (Urldecoder.decode (name, "Utf-8"));
PrintWriter out=resp.getwriter ();
if ("admin". Equals (name))
{
Out.print ("0");
} else
{
Out.print ("1");
}
Out.close ();
}
}
ajax post:
front desk:
<! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "HTTP://WWW.W3.ORG/TR/HTML4/LOOSE.DTD" >
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 ">
<title> User Registration </title>
<script type= "Text/javascript" >
var xmlhttp;
function Createxmlhttp ()
{
if (window. XMLHttpRequest)
{
Xmlhttp=new XMLHttpRequest ();
}else
{
Xmlhttp=new ActiveXObject ("Microsoft.XMLHTTP");
}
}
function CheckName ()
{
Createxmlhttp ();
var Name=document.getelementbyid ("name"). Value;
Xmlhttp.open ("Post", "Ajax/checkname");//Open link
Xmlhttp.setrequestheader ("Content-type", "application/x-www-form-urlencoded");
Xmlhttp.send ("Name=" +encodeuri (encodeURI (name)));//Send Request
xmlhttp.onreadystatechange=callback;//This function is called when a change in state occurs during a request
}
function callback ()
{
if (xmlhttp.readystate==4&&xmlhttp.status==200)
{
var re=xmlhttp.responsetext;//information returned by the server
if ("1" ==re)
{
Can register
var Show=document.getelementbyid ("Id_name"). Innerhtml= "<font color= ' green ' > Congratulations, you can register! </font> ";
}else
{
Can not register
var Show=document.getelementbyid ("Id_name"). Innerhtml= "<font color= ' red ' > Sorry, you can't register! </font> ";
}
}
}
</script>
<body>
<center>
<form action= "Regist" method= "post" enctype= "application/x-www-form-urlencoded" >
<ul>
<li> Username: <input type= "text" name= "name" id= "name" onblur= "CheckName ();" ><span id= "Id_name" ></span></li>
<li> Password: <input type= "password" name= "pwd" id= "pwd" ><span id= "Id_pwd" ></span></li>
<li><input type= "Submit" Name= "OK" value= "OK" id= "OK" ></li>
</ul>
</form>
</center>
</body>
Background:
Package Com.sp.ajax;
Import java.io.IOException;
Import Java.io.PrintWriter;
Import Java.net.URLDecoder;
Import javax.servlet.ServletException;
Import Javax.servlet.annotation.WebServlet;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
@WebServlet ("/ajax/checkname")
public class Checknameserv extends HttpServlet {
Private static final long serialversionuid = 1L;
protected void DoPost (HttpServletRequest req, HttpServletResponse resp) throws Servletexception, IOException {
Req.setcharacterencoding ("GBK");
Resp.setcontenttype ("TEXT/HTML;CHARSET=GBK");
String name=req.getparameter ("name");
System.out.println (Urldecoder.decode (name, "Utf-8"));
PrintWriter Out=resp.getwriter ();
if ("admin". Equals (name))
{
Out.print ("0");
}else
{
Out.print ("1");
}
Out.close ();
}
}
Ajax juery:
Here is omitted to write, wrote the estimate people also can not understand
Because:
Using jquery to read the external XML file, and then, to read the XML data
Back into the background, then convert from background to JSON, then print to foreground
So, it's inconvenient to write, it's omitted here.
Ajax Post/get/jquery Implementation