JSFiddle - React, Tailwind, and code Playground
HTML
<div id="box">
<canvas width="300mm" height="300mm"></canvas>
</div>
CSS
#box {
width: 150px;
height: 150px;
background-color: blue;
border-radius: 50px;
overflow: hidden;
/* -webkit-mask-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAA5JREFUeNpiYGBgAAgwAAAEAAGbA+oJAAAAAElFTkSuQmCC); */ this fixes the overflow:hidden in Chrome/Opera
}
JavaScript
var $canvas = $("canvas");
if ($canvas[0].getContext) {
var context = $canvas[0].getContext('2d');
context.fillStyle = 'red';
context.fillRect(10, 10, 300, 60);
}