[docs] graphset > preview> handleTop

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingSoft Demo</title>

  <script nonce="undefined" src="https://cdn.zingchart.com/zingchart.min.js"></script>
  <style></style>
</head>

<body>
  <div id='myChart'></div>
  <script>
    ZC.LICENSE = ["569d52cefae586f634c54f86dc99e6a9", "b55b025e438fa8a98e32482b5f768ff5"];
    let chartConfig = {
      type: "bar",
      series: [{
        values: [35, 42, 67, 89, 25, 34, 67, 85]
      }],
      scaleX: {
        zooming: true,
        zoomTo: [1, 6]
      },
      scaleY: {
        zooming: true,
        zoomTo: [20, 70]
      },
      preview: {
        handleTop: {
          backgroundColor: '#F00',
          borderColor: '#FC0',

          mediaRules: [{
            maxWidth: 400,
            backgroundColor: 'blue',
            borderColor: 'red'
          }]
        }
      }
    };

    zingchart.render({
      id: 'myChart',
      data: chartConfig,
      height: 400,
      width: "100%"
    });
  </script>
</body>

</html>

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingSoft Demo</title>

  <script src="https://cdn.zingchart.com/zingchart.min.js"></script>
</head>

<body>
  <div id='myChart'></div>
</body>

</html>

let chartConfig = {
  type: "bar",
  series: [{
    values: [35, 42, 67, 89, 25, 34, 67, 85]
  }],
  scaleX: {
    zooming: true,
    zoomTo: [1, 6]
  },
  scaleY: {
    zooming: true,
    zoomTo: [20, 70]
  },
  preview: {
    handleTop: {
      backgroundColor: '#F00',
      borderColor: '#FC0',

      mediaRules: [{
        maxWidth: 400,
        backgroundColor: 'blue',
        borderColor: 'red'
      }]
    }
  }
};

zingchart.render({
  id: 'myChart',
  data: chartConfig,
  height: 400,
  width: "100%"
});