console 命令行工具 X clear

console

function draw(){
    const ctx = document.getElementById('canvas').getContext('2d')
    ctx.arc(100,100,50,0,Math.PI*2)
    ctx.arc(100,100,20,0,Math.PI*2)
    ctx.moveTo(500,100)
    ctx.arc(500,100,50,0,Math.PI*2)
    ctx.arc(500,100,20,0,Math.PI*2)
    ctx.fill('evenodd')
}

draw();

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