Bouncing Ball - The Essential Guide to HTML5 - page 86

Code Explanation

background-color:#b10515;

padding:20px;

}

</style>

<script type="text/javascript">

var boxx = 20;

var boxy = 30;

var boxwidth = 350;

var boxheight = 250;

var ballrad = 20; This isn't a substantial change, but the

picture required a bigger radius.

var boxboundx = boxwidth+boxx-ballrad;

var boxboundy = boxheight+boxy-ballrad;

var inboxboundx = boxx+ballrad;

var inboxboundy = boxy+ballrad;

var ballx = 50;

var bally = 60;

var ballvx = 4;

var ballvy = 8;

var img = new Image(); Defining the img variable as an Image object.

This is what the new operator and the call to
the Image function do.