我们经常使用类似echarts这样的可视化图表，虽然提供给我们的生态已经够完善了，但是缺不能满足我们的自定义和好奇心，现在我们用简单的canvas来绘画柱状图(代码不想优化了建议用面向对象书写)

    var heightc, widthc;
    var w = document.getElementById("barChart")
    var heightc = w.height - 50;
    var widthc = w.width - 50;
    var s = document.getElementById("barChart").getContext('2d');
    s.beginPath();
    s.moveTo(50, 0);
    s.lineTo(50, heightc);
    s.stroke();
    s.beginPath();
    s.moveTo(50, heightc);
    s.lineTo(widthc, heightc);
    s.stroke();
    var heig = heightc;
    var withdx = widthc / 6;
    var top = 0;
    for (var i = 0; i < 6; i++) {
    var bar = (Math.random() * (500 - 1) + 1) / 2.04;
    // 水平横线
    s.beginPath();
    s.strokeStyle = 'rgb(202,205,209)';
    s.moveTo(50, heig);
    s.lineTo(widthc, heig);
    s.stroke();
    // 柱形
    s.beginPath();
    s.fillStyle = randomColor();
    s.fillRect(withdx, 350, 50, -bar);
    s.stroke()

    // y轴描述
    s.beginPath();
    s.fillStyle = '#000000'
    s.font = "15px Arial";
    s.fillText(top, 15, heig);
    s.stroke()
    // x轴描述
    s.beginPath();
    s.fillStyle = '#000000'
    s.font = "15px Arial";
    s.fillText(`${i+1}年`, withdx+10, 380);
    s.stroke()

    top += 102;
    heig -= 50;
    withdx += 80
    }

    }
    function randomColor() {

    var str = '#';

    for (var i = 0; i < 6; i++) {

    str += Math.floor(Math.random() * 16).toString(16);

    }

    return str;
}

效果图