Example of box2dweb with C++ heritage noted in comments

box2dweb-example.js

// Code from http://lib.ivank.net/?p=demos&d=box2D

// These look like imports, but in JavaScript they are just busy-work.
var   
    b2Vec2          = Box2D.Common.Math.b2Vec2,
    b2BodyDef       = Box2D.Dynamics.b2BodyDef,
    b2Body          = Box2D.Dynamics.b2Body,
    b2FixtureDef    = Box2D.Dynamics.b2FixtureDef,
    b2World         = Box2D.Dynamics.b2World,
    b2PolygonShape  = Box2D.Collision.Shapes.b2PolygonShape;

// Constructor functions should use ProperCase in JavaScript.
world = new b2World(new b2Vec2(0, 10),  true);

// Someone without a programming background may not be able to guess
// what this abbreviation means.
up = new b2Vec2(0, -7);

// Here we're creating a fixture, then a body, then a shape. For
// simple learning exercises these distinctions aren't useful.
var fixDef = new b2FixtureDef();
fixDef.density = 1.0;

var bodyDef = new b2BodyDef();
bodyDef.type = b2Body.b2_staticBody; // mixed camelCase and _s
fixDef.shape = new b2PolygonShape();

// Here ProperCase is used for methods, which should be reserved
// for constructors in JavaScript.
bodyDef.position.Set(9, stage.stageHeight/100 + 1);
fixDef.shape.SetAsBox(10, 1); 
world.CreateBody(bodyDef).CreateFixture(fixDef);

game-step-1.js

var canvas = document.getElementById("game");
var world = boxbox.createWorld(canvas);

game-step-2.js

var player = world.createEntity();

game-step-3.js

var ground = world.createEntity({
  color: "green",
  x: 13,
  y: 18,
  width: 12,
  height: 0.5,
  type: "static"
});

game-step-4.js

player.onKeydown(function(e) {
  this.applyImpulse(100, 45);
});

game-step-5.js

// Reusable template
var targetTemplate = {
  color: "blue",
  height: 1.5,
  width: 0.25
};

// Bottom level
world.createEntity(targetTemplate, {x: 18, y: 15});
world.createEntity(targetTemplate, {x: 21, y: 15});
world.createEntity(targetTemplate, {x: 24, y: 15});

// Bottom horizontal platform
world.createEntity({
  color: "purple",
  width: 3,
  height: 0.25,
  x: 21,
  y: 13
});

// Middle
world.createEntity(targetTemplate, {x: 23, y: 11});
world.createEntity(targetTemplate, {x: 19, y: 11});

// Top horizontal platform
world.createEntity({
  color: "purple",
  width: 2,
  height: 0.25,
  x: 21,
  y: 9
});

// Top level
world.createEntity(targetTemplate, {x: 21, y: 7});