issue with prepare() function: Syntax error or access violation: 1064 You have an error in your SQL syntax

Question

I need to SELECT two usernames from a mysql table, I've sent LIMIT as an object via ajax like this

let myTable= {limit:2};

And this is the sql code:

$sql = "SELECT username From members LIMIT :limit";

But i am getting above error, Do you have any idea how can i fix this?

Ajax code:

let myTable = { limit: 2 };

let sendMe = JSON.stringify(myTable);



let xhr = new XMLHttpRequest();
xhr.onreadystatechange = function () {

    if (this.readyState == 4 && this.status == 200) {


        document.getElementById('result').innerHTML = xhr.responseText;
    }


}

xhr.open("GET", "check.php?x=" + sendMe, true);
xhr.send();

PHP code (check.php):

<?php

$server = 'localhost';
$username = 'root';
$password = 'mysql';
$dbname = 'myapp';

$obj = json_decode($_GET['x']);




try {
   $conn = new PDO("mysql:host=$server; dbname=$dbname", $username, $password);
   $conn->setAttribute(pdo::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
   $sql = "SELECT username From members LIMIT :limit";
   $stmt = $conn->prepare($sql);
   $stmt->bindParam(':limit', $limit);

   $limit = $obj->limit;
   $stmt->execute();

   $result = $stmt->fetchAll();



   foreach ($result as $row) {
      echo $row['username'] . "<br>";
   }
} catch (PDOException $e) {
   echo $e->getMessage();
}

$conn = null;