<!DOCTYPE html>
<html>
<body>
<canvas id="canvas" width="100.5" height="200.5px"></canvas>
</body>
<script>
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
context.fillStyle = 'green';
context.fillRect(0, 0, 50, 50);
</script>
</html>