<canvas id="canvas" width="100" height="100"></canvas>
<script>
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.font = '10px sans-serif';
ctx.filter = 'drop-shadow(0em .5em black)';
ctx.font = '20px sans-serif';
ctx.fillStyle = '#0f0';
ctx.fillRect(25, 25, 50, 40);
</script>