JavaScript Simple Didatic Game Loop

gameloop.js

var canvas;
var contexto;
var naveX = 400;
var naveY = 400;

function init() {
    canvas   = document.getElementById("game");
    contexto = canvas.getContext('2d');
    nave = document.getElementById("nave");
    
    setInterval(loop, 1000/60 );
}

function loop() {
    update();
    draw();
}

function update() {
    naveX++;
    naveY--;
}

function draw() {
    contexto.clearRect(0, 0, canvas.width, canvas.height);
    contexto.drawImage( nave, naveX, naveY);
}

init();