[Docs] Register Custom Filterer

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingGrid: Docs Getting Started</title>
  <!--Script Reference[1]-->
  <script nonce="undefined" src="https://cdn.zinggrid.com/zinggrid.min.js"></script>
  <style>
    html,
    body {
      height: 100%;
      width: 100%;
      margin: 0;
      padding: 0;
    }



    zing-grid[loading] {
      height: 317px;
    }
  </style>
</head>

<body>
  <zing-grid caption="Register Custom Filterer" filter="inline">
    <zg-colgroup>
      <zg-column index="first" filterer="number"></zg-column>
      <zg-column index="last" filterer="lettersOnly"></zg-column>
      <zg-column index="number"></zg-column>
    </zg-colgroup>
    <zg-data data='[
        { "first": "Maria", "last": "John", "number": 123 },
        { "first": "David", "last": "Smith", "number": 456 },
        { "first": "Felicity", "last": "Snow", "number": 789 }
      ]'></zg-data>
  </zing-grid>
  <script>
    ZingGrid.setLicense(['26ccbfec16b8be9ee98c7d57bee6e498']);
    let customFilter = {
      afterInit(oDOMFilter) {
        let oDOMInput = oDOMFilter.querySelector('input');
        oDOMInput.addEventListener('keypress', (e) => {
          if (!/^[a-z]$/i.test(e.key))
            e.preventDefault();
        });
      },
    };
    ZingGrid.registerFilterer(customFilter, 'lettersOnly');
  </script>
</body>

</html>

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingGrid: Docs Getting Started</title>
  <!--Script Reference[1]-->
  <script src="https://cdn.zinggrid.com/zinggrid.min.js"></script>
</head>

<body>
  <zing-grid caption="Register Custom Filterer" filter="inline">
    <zg-colgroup>
      <zg-column index="first" filterer="number"></zg-column>
      <zg-column index="last" filterer="lettersOnly"></zg-column>
      <zg-column index="number"></zg-column>
    </zg-colgroup>
    <zg-data data='[
        { "first": "Maria", "last": "John", "number": 123 },
        { "first": "David", "last": "Smith", "number": 456 },
        { "first": "Felicity", "last": "Snow", "number": 789 }
      ]'></zg-data>
  </zing-grid>
</body>

</html>

html,
body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
}

let customFilter = {
  afterInit(oDOMFilter) {
    let oDOMInput = oDOMFilter.querySelector('input');
    oDOMInput.addEventListener('keypress', (e) => {
      if (!/^[a-z]$/i.test(e.key))
        e.preventDefault();
    });
  },
};
ZingGrid.registerFilterer(customFilter, 'lettersOnly');