2d shooter

by tmanrocks999

HTML

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>
canvas {
    border:4px solid #d3d3d3;
    background-color: #f1f1f1;
}
</style>
</head>
<body onload="startGame()">
<script>

var myGamePiece;
var endGoalPiece;
var myEnemy1;
var bullet;
var myEnemy1Hp = 10;
var damage = 1;
var playerExp = 0;

function startGame() {
    myGameArea.start();
    myGamePiece = new component(30, 30, "red", 0, 240);
    endGoalPiece = new component(30, 30, "black", 450, 240);
    myEnemy1 = new component(30, 30, "green", 200, 240);
}

var myGameArea = {
    canvas : document.createElement("canvas"),
    start : function() {
        this.canvas.width = 480;
        this.canvas.height = 270;
        this.context = this.canvas.getContext("2d");
        document.body.insertBefore(this.canvas, document.body.childNodes[0]);
        this.interval = setInterval(updateGameArea, 20);
        window.addEventListener('keydown', function (e) {
            myGameArea.key = e.keyCode;
        })
        window.addEventListener('keyup', function (e) {
            myGameArea.key = false;
        })
    },
    clear : function(){
        this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
    }
}

function component(width, height, color, x, y) {
    this.gamearea = myGameArea;
    this.width = width;
    this.height = height;
    this.speedX = 0;
    this.speedY = 0;
    //this.gravity = 0.05;
  	//this.gravitySpeed = 0;
    this.x = x;
    this.y = y;
    this.color = color;
    this.update = function() {
        ctx = myGameArea.context;
        ctx.fillStyle = this.color;
        ctx.fillRect(this.x, this.y, this.width, this.height);
    }
    this.newPos = function() {
        this.gravitySpeed += this.gravity;
        this.x += this.speedX;
        this.y += this.speedY; //+ this.gravitySpeed;
        this.hitBottom();
        this.hitTop();
        this.hitRight();
        this.hitLeft();
        this.hitGoal();
       ...