$("#btnLogin").click(function(){
        var txtLogin = $("#txtLogin").val();
        var txtPassword = $("#txtPassword").val();

        $.post("./controller/compruebaLogin.php", {user: txtLogin, contrapass: txtPassword}, function(data){
            alert(data.result);
            if(data.result === "ok"){
                location.href = "/sections/main.php";
            }else{
                location.href = "index.php";
            }
        });
    });