AJAX實現簡單的注冊頁面異步請求實例代碼

<?php
var_dump($_GET);
$user = $_GET['user'];
$pwd = $_GET['pwd'];
$tel = $_GET['tel'];
$email = $_GET['email'];
$msg = '';
header('Content-type:text/html;charset=utf8');
 $adders = "mysql:host=localhost;dbname=Users;";
 $db = new PDO($adders,"root");
 $db->exec('set names utf8');
 //鏈接數據庫,創建表
 $result = $db->exec('create table if not exists ajaxreg(user varchar(100) 
 primary key,pwd varchar(100),tel varchar(30),email varchar(30)) 
 default charset=utf8');
 $resulttel = $db->query("select tel from ajaxreg ");
 $resulttel->setFetchMode(PDO::FETCH_ASSOC);
 $arr = $resulttel->fetchAll();
 
 foreach($arr as $ar){
 if( $ar['tel'] == $tel){
 $msg = "您輸入的手機號已經存在";
 echo $msg;
 //如果手機號已存在,終止整個程序
 die();
 }
 }
 //如果手機號不存在執行下面代碼
 $result = $db->exec("insert into ajaxreg values(
 '$user','$pwd','$tel','$email')");
 if($result){
 $msg = "注冊成功";
 }else{
 $msg = "用戶名已存在";
 }
 echo $msg;
 $db->close();
?>