SOURCE

const canvas = document.getElementById("canvas");
const isSupportCanvas = !!canvas.getContext;

if (isSecureContext) {
    const ctx = canvas.getContext("2d");

    ctx.beginPath();
    ctx.arc(75, 75, 50, 0, Math.PI * 2, true); // 绘制
    ctx.moveTo(110, 75);
    ctx.arc(75, 75, 35, 0, Math.PI, false); // 口 (顺时针)
    ctx.moveTo(65, 65);
    ctx.arc(60, 65, 5, 0, Math.PI * 2, true); // 左眼
    ctx.moveTo(95, 65);
    ctx.arc(90, 65, 5, 0, Math.PI * 2, true); // 右眼
    ctx.stroke();
}

<canvas id="canvas"></canvas>