console 命令行工具 X clear

console

function draw(){
    const ctx = document.getElementById('canvas').getContext('2d')
    ctx.fillRect(0,0,150,150)
    ctx.save()
    ctx.fillStyle = 'rgba(0,255,0,0.3)'
    ctx.fillRect(20,20,110,110)
    ctx.save()
    ctx.restore()
    ctx.fillRect(40,40,70,70)
    ctx.restore()
    ctx.fillRect(60,60,30,30)
}


draw()

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