How to add a html5 CANVAS within a DIV

I'm using the below code to generate a canvas. At the moment it adds the canvas element to the body, how can I get it to add it to a div named "divGameStage", which is not nested within any other elements, except body.

EDIT: I've tried the first suggestion, but no canvas is appearing, full code is as follows:

<head>
<meta charset="utf-8">
<title>Game Stage</title>
<script type="text/javascript">
    function loadCanvas(id) {
        var canvas = document.createElement('canvas');
        div = document.getElementByID(id); 
        canvas.id     = "CursorLayer";
        canvas.width  = 1224;
        canvas.height = 768;
        canvas.style.zIndex   = 8;
        canvas.style.position = "absolute";
        canvas.style.border   = "1px solid";
        div.appendChild(canvas)
    }
        </script>
</head>
<body>
<header>
    <h1>The most important heading on this page</h1>
    <p>With some supplementary information</p>
</header>
<div id="divControls"></div>
<div id="divGameStage"></div>
<script type="text/javascript">
    loadCanvas(divGameStage);
</script>
</body>
</html>