Ajax请求工作但没有输出

Hello I'm a beginner in Ajax and PHP so sorry if my question is useless or stupid. But I am trying to do a live search with ajax and I have looked over and over internet but nothing could help me... so here I am! :-) I have 4 files one for the html, one to connect to the database, one for jQuery and the last one for the script in php. I have looked on the console with chrome and I can see that the ajax works but there is no output and I have no idea why... I'll leave you the code below and an early thank you! Also there might be some French in the code but it's just the variables and I will secure my connection to the database later. Thank you again. Html :

<html>
<head>
    <meta charset="utf-8" />
    <title>live search test</title>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
    <script type="text/javascript" src="search.js"></script>    
</head>
<body>


    <h1>LIVE SEARCH WITH AJAX TEST</h1>
    <div class="search">
    <input type="search" name="search" id="recherche">
    </div>
    <br>
    <div class="resultat" id="resultat">

    </div>
</body>
</html>

PHP to connect to the database:

<?php
$host="localhost";
$user="root";
$password="";
$db="smartphone";

$conn=mysqli_connect($host,$user,$password,$db);
?> 

jQuery:

$(document).ready(function(){
    $("#recherche").keyup(function(){
        var recherche = $(this).val();
        var data = 'motclef = ' + recherche;
        if (recherche.length > 1) {

          $.ajax({
          type : "GET",
          url : "fetch.php",
          data : data, 
          success : function(server_response){
             $("#resultat").html(server_response).show();
          }
          });

        } 

    });
  });

And the script in PHP:

include'connect.php';

if (isset($_GET['motclef'])) {
    $motclef = $_GET['motclef'];
    $q = array('motclef' => $motclef. '%');
    $sql = "SELECT name FROM smartphone WHERE name LIKE :motclef";
    $req = $conn ->prepare($sql);
    $req -> execute($q);
    $count = $req->rowCount($sql);

    if ($count == 1) {
        while ($result = $req -> fetch(PDO::FETCH_OBJ)) {
            echo 'Smartphone :'.$result ->title.' ';
        }
    }else {
    echo "Aucun resultat trouvé pour:". $motclef;
    }
}
?>

Remove whitespace from 'motclef = '
var data = 'motclef= ' + recherche;

Other wise put underscore $_GET['motclef_'] in your PHP code(if you don't remove space then)

if (isset($_GET['motclef_'])) {
    $motclef = $_GET['motclef_'];
    $q = array('motclef' => $motclef. '%');
    $sql = "SELECT name FROM smartphone WHERE name LIKE :motclef";
    $req = $conn->prepare($sql);
    $req->execute($q);
    $count = $req->rowCount($sql);

    if ($count == 1) {
        while ($result = $req->fetch(PDO::FETCH_OBJ)) {
            echo 'Smartphone :'.$result->title.' ';
        }
    }else {
    echo "Aucun resultat trouvé pour:". $motclef;
    }
}