Mouse follow move

move with restrictions follow the mouse fullscreen, because of jsfiddle frames this is not very obvious, but does work

HTML

<body> <span class="mouse"></span>

<span class="other"></span>

    <canvas id="myCanvas" width="500" height="500"></canvas>
</body>

JavaScript

a // Create the canvas

var canvas = document.createElement("canvas");

var ctx = canvas.getContext("2d");


ctx.canvas.width = 500;

ctx.canvas.height = 500;

document.body.appendChild(canvas);



// Background image

var rot = 1;

var bgReady = false;

var bgImage = new Image();

bgImage.onload = function () {

    bgReady = true;

};
bgImage.src = "http://piq.codeus.net/static/media/userpics/piq_125305_400x400.png";

// tank

var tankReady = false;

var tankImage = new Image();

tankImage.onload = function () {

    tankReady = true;
};

tankImage.src = "http://piq.codeus.net/static/media/userpics/piq_125305_400x400.png";

var tank = {

    speed: 100, // movement in pixels per second
    x: 10,
    y: 10

};

// Handle keyboard controls

var keysDown = {};



addEventListener("keydown", function (event) {

    keysDown[event.keyCode] = true;

}, false);



addEventListener("keyup", function (event) {

    delete keysDown[event.keyCode];

}, false);


// Update game objects


var update = function (modifier) {





    rot += 1;
    if (tank.x >= 1485) {
        tank.x = 1484;
    }
    if (tank.x <= 0) {
        tank.x = 1;
    }
    if (tank.y <= 0) {
        tank.y = 1;
    }
    if (tank.y >= 610) {
        tank.y = 609;
    }

    //controls
    if (87 in keysDown) { // Player holding up

        tank.y -= tank.speed * modifier;

    }

    if (83 in keysDown) { // Player holding down

        tank.y += tank.speed * modifier;

    }

    if (65 in keysDown) { // Player holding left

        tank.x -= tank.speed * modifier;

    }

    if (68 in keysDown) { // Player holding right

        tank.x += tank.speed * modifier;

    }



};

function drawRotatedImage(image, x, y, angle) {

    // save the current co-ordinate system 
    // before we screw with it
    ctx.save();

    // move to the middle of where we want to draw our image
    ctx.translate(x, y);

    // rotate around that point, converting our 
    // angle from degrees to radians 
   ...