Chartjs-Chart.js how do we extract clicked var?

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Add an variable outside of your chartFunctions, set that variable in the click handler and then use it

let xVal = ''

var options = {
  type: 'bar',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        borderWidth: 1
      },
      {
        label: '# of Points',
        data: [7, 11, 5, 8, 3, 7],
        borderWidth: 1
      }
    ]
  },
  options: {
    onClick: function(c, i) {

      e = i[0];
      //console.log(e._index)
      var x_value = this.data.labels[e._index];
      var y_value = this.data.datasets[0].data[e._index];
      // console.log(x_value);
      //console.log(y_value);
      console.log('you clicked the graph, now the x value is = ' + x_value)
      xVal = x_value
    },
    scales: {
      yAxes: [{
        ticks: {
          reverse: false
        }
      }]
    }
  }
}

document.getElementById('temp').addEventListener('click', () => {
  console.log('X val: ', xVal);
  alert('X val: ' + xVal)
})

var ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);
canvas {
  background-color: #eee;
}
<body>
  <canvas id="chartJSContainer" width="600" height="400"></canvas>
  <button id="temp">
    show pressed X value
    </button>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js" integrity="sha512-hZf9Qhp3rlDJBvAKvmiG+goaaKRZA6LKUO35oK6EsM0/kjPK32Yw7URqrq3Q+Nvbbt8Usss+IekL7CRn83dYmw==" crossorigin="anonymous"></script>
</body>

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