Bouton ne marche pas

$('button:last').on('click',function(){
    console.log("salut");
});

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Page Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- bootstrap 4 css-->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
    <link rel="stylesheet" type="text/css" media="screen" href="main.css" />
    <!-- bootstrap 4 -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
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    <!-- script perso + jquery.js-->
    <script type="application/javascript" src="script.js"></script>
    <script type="application/javascript" src="jquery.js"></script>
</head>
<body>
<section class="content">
    <article class="container"><br>
        <div class="row" id="login_top">
            <div class="col-lg-4"></div>
            <div class="col-lg-4">
            <p id="login_text">Appli</p>
                <input class="form-control" id="log1" type="text" name="username" placeholder="Username" required=""><br>
                <input class="form-control" id="mdp1" type="password" name="password" placeholder="Password" required=""><br>
                <button class="btn btn-success btn-block">Se connecter</button>
                <button class="btn btn-secondary btn-block">S'enregistrer</button>
            </div>
            </div>
        </article>
    </section>
</body>
</html>