Three.js - Insert separate js file in HTML

I am working with three.js right now and have a 3D cube rendered in HTML. The HTML code looks like this:

<div id="render" class="center-block">



<script>



var camera;

var scene;

var renderer;

var mesh;

var geometry;

var material1;

var material2;

var material3;

var material4;

var material5;

var material6;

var materials;

var meshFaceMaterial;



init();

animate();



function init() {

    scene = new THREE.Scene();

    camera = new THREE.PerspectiveCamera( 20, window.innerWidth / window.innerHeight, 0.1, 1000);

    camera.position.set( 0, 0, 0 );



    var light = new THREE.DirectionalLight( 0xffffff );

    light.position.set( 0, 1, 1 ).normalize();

    scene.add(light);



    geometry = new THREE.CubeGeometry( 10, 10, 10);

    material1 = new THREE.MeshPhongMaterial( { map: THREE.ImageUtils.loadTexture('http://vignette1.wikia.nocookie.net/scifiminibuilders/images/8/88/Your_Picture_Here.png/revision/latest?cb=20130507015051') } );

    material2 = new THREE.MeshPhongMaterial( { map: THREE.ImageUtils.loadTexture('http://vignette1.wikia.nocookie.net/scifiminibuilders/images/8/88/Your_Picture_Here.png/revision/latest?cb=20130507015051') } );

    material3 = new THREE.MeshPhongMaterial( { map: THREE.ImageUtils.loadTexture('http://vignette1.wikia.nocookie.net/scifiminibuilders/images/8/88/Your_Picture_Here.png/revision/latest?cb=20130507015051') } );

    material4 = new THREE.MeshPhongMaterial( { map: THREE.ImageUtils.loadTexture('http://vignette1.wikia.nocookie.net/scifiminibuilders/images/8/88/Your_Picture_Here.png/revision/latest?cb=20130507015051') } );

    material5 = new THREE.MeshPhongMaterial( { map: THREE.ImageUtils.loadTexture('http://vignette1.wikia.nocookie.net/scifiminibuilders/images/8/88/Your_Picture_Here.png/revision/latest?cb=20130507015051') } );

    material6 = new THREE.MeshPhongMaterial( { map: THREE.ImageUtils.loadTexture('http://vignette1.wikia.nocookie.net/scifiminibuilders/images/8/88/Your_Picture_Here.png/revision/latest?cb=20130507015051') } );



    materials = [material1, material2, material3, material4, material5, material6];



    meshFaceMaterial = new THREE.MeshFaceMaterial( materials );



    mesh = new THREE.Mesh(geometry, meshFaceMaterial );

    mesh.position.z = -50;

    scene.add( mesh );



    renderer = new THREE.WebGLRenderer();

    renderer.setSize( window.innerWidth, window.innerHeight );

    document.getElementById('render').appendChild( renderer.domElement );

    window.addEventListener( 'resize', onWindowResize, false );



    render();

}



function onWindowResize() {

    camera.aspect = window.innerWidth / window.innerHeight;

    camera.updateProjectionMatrix();

    renderer.setSize(window.innerWidth, window.innerHeight);

    render();

}



function animate() {

    mesh.rotation.x += .016;

    mesh.rotation.y += .015;

    mesh.rotation.y += .014;



    render();

    requestAnimationFrame( animate );

}



function render() {

    renderer.render( scene, camera );

}



</script>

</div>

There is quite too much script. I want to make a separate .js file from that, but don't know how do accomplish it with three.js. Any suggestions?

EDIT:

As I understand, the script works like a canvas tag, without entering the tag in HTML. This probably disturbs by making a separate .js file...