function createCircle(size, color) { const canvas = document.createElement("CANVAS"); canvas.width = size; canvas.height = size; const context = canvas.getContext('2d'); context.clearRect(0, 0, canvas.width, canvas.height); context.fillStyle = color; context.beginPath(); context.arc(200, 200, 80, 0, 2 * Math.PI); context.fill(); return canvas.toDataURL('image/png'); } const base64 = createCircle(100, 'red'); console.log(base64); document.getElementById('test').src = base64;

 <img width="100" height="100" id="test" style="border: 1px solid black">