Edit in JSFiddle

var camera, scene, renderer;
var geometry, material, mesh;

init();
animate();

function init() {

    camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 1, 10000);
    camera.position.z = 1000;

    scene = new THREE.Scene();

    geometry = new THREE.CubeGeometry(200, 200, 200);
    material = new THREE.MeshBasicMaterial({
        color: 0xff0000,
        wireframe: true
    });

    mesh = new THREE.Mesh(geometry, material);
    scene.add(mesh);

    renderer = new THREE.CanvasRenderer();
    renderer.setSize(window.innerWidth, window.innerHeight);

    document.body.appendChild(renderer.domElement);

}

function animate() {

    // note: three.js includes requestAnimationFrame shim
    requestAnimationFrame(animate);

    mesh.rotation.x += 0.01;
    mesh.rotation.y += 0.02;

    renderer.render(scene, camera);

}

body {
    overflow: hidden;
}