Simple PHP / MYSQL / jQUERY Login Script

In this tuto, we will let to know about Ajax login form using jQuey and PHP,
for this login form we need 3 files and they will be :
  1. index.php : 
    2.  <!DOCTYPE html>  
 <html>  
  <link rel="stylesheet" href="css/style.css" media="screen" type="text/css" />  
  <script src=" https://code.jquery.com/jquery-2.1.4.min.js"></script>  
 <script src="js/app.js"></script>  
 <head>  
      <meta charset="utf-8">  
      <title>Tuto4free Login</title>  
 </head>  
 <body>  
   <div id="login-form">  
     <h3>Tuto4free</h3>  
     <fieldset>  
       <form action="login.php">  
         <input type="email" id="Email" required   placeholder="Email">   
         <input type="password" id="password" required   placeholder="Password">  
         <input type="submit" id="Log_btn" value="Login">  
         <footer>  
            <div id="err"></div>  
           <p><span class="info">?</span><a href="http://www.tuto4free.com">Lost my password</a></p>  
         </footer>  
       </form>  
     </fieldset>  
   </div>   
 </body>  
 </html>  
 </body>  
 </html>
  2. login.php : 
    3.  <?php   
      $pdo = new PDO('mysql:host=localhost;dbname=login', 'root','');  
      $SQL="SELECT * FROM `user` where email=? and Password=? ";  
      $req = $pdo->prepare($SQL);  
      $req->execute(array($_POST['username'],md5($_POST['password'])));  
      $res=$req->fetchAll();       
      if(count($res)==1)  
      {  
           echo "true";  
      }  
      else  
      {  
           echo "false";  
      }
  3. app.js :  
    4.  $(document).ready(function(){  
   $("#Log_btn").click(function(){  
     username=$("#Email").val();  
     password=$("#password").val();  
      $.ajax({  
       type: "POST",  
       url: "login.php",  
       data: "username="+username+"&password="+password,  
       success: function(html){  
        if(html=='true')  
        {  
         $("#login-form").fadeOut();  
        }  
        else  
        {  
           $("#err").html("Wrong username or password");  
        }  
       },  
       beforeSend:function()  
       {  
          $("#err").html("Loading...")  
       }  
     });  
      return false;  
   });  
 });

Khebbou