Ajax的封裝以及普通用戶登錄簡單例子

 1 function ajax()
 2 {
 3     var xmlHttp=null;
 4     if(windows.XMLHttpRequest){
 5         xmlHttp=new XMLHttpRequest();
 6        }
 7       else{
 8             if(windows.ActiveXObject){
 9                 xmlHttpReq=new ActiveXObject("Microsoft.XMLHTTP");
10             }
11         }
12        var handler=null;
13        this.fun=function(url,mode.synchro,_handler){
14             handler=_handler;
15             xmlHttp.open(mode,url,synchro);
16             xmlHttp.send(null);
17         };
18         this.callback=function(){
19             if(xmlHttp.readyState==4){
20                    if(xmlHttp.status==200){
21                             handler(xmlHttp.responseText);
22                     }else{
23                            alert("請求失敗");
24                      }
25             }
26 }
27 
28 function ajaxPost(url,postStr,onsuccess)
29 {
30     var xmlHttp=window.XMLHttpRequest():new ActiveXObject('Microsoft.XMLHttp');
31     xmlHttp.open("POST",url,true);
32     xmlHttp.onreadystatechange=function()
33     {
34         if(xmlHttp.readyState==4){
35                if(xmlHttp.status==200){
36                          onsuccess(xmlHttp.responseText);
37                   }
38                else{
39                         alert('Ajax伺服器返回錯誤!');
40                       }
41     
42               }
43 }
44       xmlHttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
45       xmlHttp.send(postStr);
46 }
47                                                 

 1 <?php
 2     //連接資料庫
 3     $conn=mysql_connect('127.0.0.1','username','password');
 4     if($conn){
 5         mysql_select_db("test",$conn);
 6         mysql_query("set names 'utf-8'");
 7       }
 8     else{
 9            die();
10     };
11     //用戶驗證
12     $username=$_POST['username'];
13     $password=$_POST['password'];
14 
15     $sql="select * from Users where username='$username'";
16     
17     $result=mysql_query($sql) or die("用戶名不存在");
18     $num=mysql_num_rows($result);
19     if($num){
20         echo 1;
21         $_SESSION['Z_USERNAME']=$username;//保存登錄用戶
22     }else{
23         echo 2;
24          mysql_close();
25     }
26 }
27 ?>
28             

 1 function loginCheck(){
 2     var username=document.getElementById('username').value;
 3     var password=document.getElementById('password').value;
 4     var postStr="username="+username+"&password="+password;
 5     if(username==""){
 6             alert("用戶名不能為空，請重新輸入");
 7              return false;
 8     }
 9     else if(password==""){
10             alert("密碼不能為空，請重新輸入！");
11             return false;
12     }
13     else{
14         ajaxPost("login.php",postStr,function(result){
15             if(result=="1"){
16                 alert('恭喜您，登錄成功！');
17             }
18             else if(result=="2"){
19                    alert("密碼輸入有誤，請重新輸入！");
20             }
21      });
22    }
23 }