↑このようになります

ソース

<!DOCTYPE html><head>
<meta http-equiv="Content-Type" content="text/html; charset=shift_jis">
<script type="text/javascript">
window.onload = draw;
function draw(){
var canvas1 = document.getElementById('graph1');
var line1 = canvas1.getContext('2d');
line1.fillRect(20,10,150,40);
}
</script>
</head>
<body>
<canvas id="graph1" width="300" height="100"></canvas>
</body>
</html>