图表：图表未绘制示例

Question

此Meteor客户端代码尝试使chart.js example正常工作，但它没有绘制任何内容。即空白页 包装：图表：图表
知道为什么以及如何让图表显示在页面上？感谢

Template.jack.onRendered(function () {
  console.log('jack rendered');
  var ctx = document.getElementById("myChart").getContext('2d');
  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
          }
        }]
      }
    }
  });
});

<template name="jack">
  <canvas id="myChart" width="400" height="400"></canvas>
</template>
// element inspector shows:
 <canvas id="myChart" width="359" height="359" style="width: 400px; height: 400px;"></canvas>