制作图表 柱状图等

官网：https://www.chartjs.org/docs/latest/charts/line.html

参考：https://blog.csdn.net/weixin_42577411/article/details/115695505

引入（application.html.erb）

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/chart.js@2.9.1/dist/Chart.min.css">
<script src="https://cdn.jsdelivr.net/npm/chart.js@2.9.1/dist/Chart.min.js"></script>

创建页面

<canvas id="myChart" width="960" height="200"></canvas>

增加代码

<script>
var ctx = document.getElementById('myChart');
var myChart = new Chart(ctx, {
  type: 'bar',
  data: {
    labels: ['Red', 'Blue', 'Yellow', 'Green', 'Purple', 'Orange'],
    datasets: [{
      label: '# of Votes',
      data: [12, 19, 3, 5, 2, 3],
      backgroundColor: ['rgba(255, 99, 132, 0.2)', 'rgba(54, 162, 235, 0.2)', 'rgba(255, 206, 86, 0.2)', 'rgba(75, 192, 192, 0.2)', 'rgba(153, 102, 255, 0.2)', 'rgba(255, 159, 64, 0.2)'],
      borderColor: ['rgba(255, 99, 132, 1)', 'rgba(54, 162, 235, 1)', 'rgba(255, 206, 86, 1)', 'rgba(75, 192, 192, 1)', 'rgba(153, 102, 255, 1)', 'rgba(255, 159, 64, 1)'],
      borderWidth: 1
    }]
  },
  options: {
    scales: {
      yAxes: [{
        ticks: {
          beginAtZero: true
        }
      }]
    }
  }
});
</script>

也可以换成线状的

<script>
var ctx = document.getElementById('myChart');
var myChart = new Chart(ctx, {
 type: 'line',
 data: {
  labels: ['Red', 'Blue', 'Yellow', 'Green', 'Purple', 'Orange'],
  datasets: [{
   label: '# of Votes',
   data: [12, 19, 3, 5, 2, 12],
   fill:false,
   borderColor:"#308af3",
   pointBackgroundColor: "#308af3",
   pointBorderWidth: 2,
   pointHoverBackgroundColor: "#fff",
   pointHoverBorderWidth: 2,
   lineTension:0.05
  }, {
   label: '# of Votes',
   data: [19, 12, 6, 15, 7, 9],
   fill:false,
   borderColor:"#48ba16",
   pointBackgroundColor: "#48ba16",
   pointBorderWidth: 2,
   pointHoverBackgroundColor: "#fff",
   pointHoverBorderWidth: 2,
   lineTension:0.05
  }]
 },
 options: {
  legend: { display: false },
  scales: {
   xAxes: [{
    gridLines: { display:false },
   }],
   yAxes: [{
    gridLines: {
     color: "rgba(0, 0, 0, .05)",
    }
   }]
  },
 }
});
</script>