<!DOCTYPE HTML> <title>Test for clipping of border-radius</title> <style> div { overflow: hidden; width: 200px; height: 100px; border-radius: 50px / 20px; } canvas { border-radius: 20px / 40px; } </style> <div><canvas id="canvas" height="100" width="200"></canvas></div> <script> var canvas = document.getElementById("canvas"); var cx = canvas.getContext("2d"); cx.fillStyle="lime"; cx.fillRect(0, 0, 200, 100); </script>