Gltf animation not working

I’m a beginner for three.js , my question is gltf model animation is working on https://gltf-viewer.donmccurdy.com/ , but not working on my code
this is model copter.glb (143.6 KB)

`

threejs - copter
<style>
    body {
        margin: 0;
        overflow: hidden;
    }
</style>
<canvas id="myCanvas"></canvas>

<script src="three.js"></script>
<script src="GLTFLoader.js"></script>
<script src="AnimationMixer.js"></script>

<script>
    var renderer,
        scene,
        camera,
        model,
        animations,
        myCanvas = document.getElementById('myCanvas');

    //RENDERER
    renderer = new THREE.WebGLRenderer({
        canvas: myCanvas,
        antialias: true
    });
    renderer.setClearColor(0x000000);
    renderer.setPixelRatio(window.devicePixelRatio);
    renderer.setSize(window.innerWidth, window.innerHeight);

    //CAMERA
    camera = new THREE.PerspectiveCamera(35, window.innerWidth / window.innerHeight, 0.1, 1000);

    //SCENE
    scene = new THREE.Scene();

    //LIGHTS
    var light = new THREE.AmbientLight(0xffffff, 0.5);
    scene.add(light);

    var light2 = new THREE.PointLight(0xffffff, 0.5);
    scene.add(light2);

    var loader = new THREE.GLTFLoader();

    loader.load('copter.glb', handle_load);

    var mesh;

    function handle_load(gltf) {

        console.log(gltf);
        mesh = gltf.scene;
        // console.log(mesh.children[0]);
        // mesh.children[0].material = new THREE.MeshLambertMaterial();
        scene.add(mesh);
        mesh.position.z = -10;
        var model = gltf.scene;
        var animations = gltf.animations;

        scene.add(model);

        //

        mixer = new THREE.AnimationMixer(model);

        var action = mixer.clipAction(animations[0]); // access first animation clip
        action.play();
    }



    //RENDER LOOP
    render();

    var delta = 0;
    var prevTime = Date.now();

    function render() {

        delta += 0.1;

        if (mesh) {

            // mesh.rotation.y += 0.01;

            //animation mesh
            // mesh.morphTargetInfluences[ 0 ] = Math.sin(delta) * 20.0;
        }

        renderer.render(scene, camera);

        requestAnimationFrame(render);
    }
</script>
`

plz help

``

What do you mean “not working”? Please be more specific.