Fixed header on resizable HTML table including auto-horizontal scroll overflow

I have built an html table using the following example as a guide, however I haven't been able to figure out how to make the head fixed so that it remains visible as a user scrolls:

https://jsfiddle.net/thatOneGuy/u5bvwh8m/16/

I have tried using CSS to control

.resizable{overflow-y: auto; position: sticky; height: 750px;}

I have also tried adding custom style to the head, however that breaks the resizing:

table thead tr{
    display:block;
}

table th,table td{
    width:100px;//fixed width
}


table  tbody{
  display:block;
  height:200px;
  overflow:auto;//set tbody to auto
}

Any help is very much appreciated.

Solution

try this

thead th{     
  position: sticky !important; 
  top: 0; 
  background-color: white;
}

and remove the resizable class from table tag and put it in thead and tbody tags

<table id="tableId" >
   <thead class="resizable">
    ...
   <tbody class="resizable">

//var tables = document.getElementsByClassName('flexiCol');
var tables = document.getElementsByClassName('resizable');
for (var i = 0; i < tables.length; i++) {
  resizableGrid(tables[i]);
}

function resizableGrid(table) {
  var row = table.getElementsByTagName('tr')[0],
    cols = row ? row.children : undefined;
  if (!cols) return;

  table.style.overflow = 'hidden';

  var tableHeight = table.offsetHeight;

  for (var i = 0; i < cols.length; i++) {
    var div = createDiv(tableHeight);
    cols[i].appendChild(div);
    cols[i].style.position = 'relative';
    setListeners(div);
  }

  function setListeners(div) {
    var pageX, curCol, nxtCol, curColWidth, nxtColWidth, tableWidth;

    div.addEventListener('mousedown', function(e) { 
    
        tableWidth = document.getElementById('tableId').offsetWidth;
      curCol = e.target.parentElement;
      nxtCol = curCol.nextElementSibling;
      pageX = e.pageX;

      var padding = paddingDiff(curCol);

      curColWidth = curCol.offsetWidth - padding;
    //  if (nxtCol)
        //nxtColWidth = nxtCol.offsetWidth - padding;
    });

    div.addEventListener('mouseover', function(e) {
      e.target.style.borderRight = '2px solid #0000ff';
    })

    div.addEventListener('mouseout', function(e) {
      e.target.style.borderRight = '';
    })

    document.addEventListener('mousemove', function(e) {
      if (curCol) {
        var diffX = e.pageX - pageX;

       // if (nxtCol)
          //nxtCol.style.width = (nxtColWidth - (diffX)) + 'px';

        curCol.style.width = (curColWidth + diffX) + 'px';
        console.log(curCol.style.width)
        console.log(tableWidth)
        document.getElementById('tableId').style.width = tableWidth + diffX + "px"
      }
    });

    document.addEventListener('mouseup', function(e) {
      curCol = undefined;
      nxtCol = undefined;
      pageX = undefined;
      nxtColWidth = undefined;
      curColWidth = undefined
    });
  }

  function createDiv(height) {
    var div = document.createElement('div');
    div.style.top = 0;
    div.style.right = 0;
    div.style.width = '5px';
    div.style.position = 'absolute';
    div.style.cursor = 'col-resize';
    div.style.userSelect = 'none';
    div.style.height = height + 'px';
    return div;
  }

  function paddingDiff(col) {

    if (getStyleVal(col, 'box-sizing') == 'border-box') {
      return 0;
    }

    var padLeft = getStyleVal(col, 'padding-left');
    var padRight = getStyleVal(col, 'padding-right');
    return (parseInt(padLeft) + parseInt(padRight));

  }

  function getStyleVal(elm, css) {
    return (window.getComputedStyle(elm, null).getPropertyValue(css))
  }
};

 * {
    box-sizing: border-box;
  }

  table {
    border-collapse: collapse;
  }

  td,
  th {
    padding: 5px 15px;
    text-align: left;
  }

  table,
  th,
  td {
    border: 1px solid #000;
  }
   
  thead th  { 
      position: sticky !important;
      top: 0;
      background-color: white;
    }

<table id="tableId" >
  <thead class="resizable">
    <tr>
      <th><input type="checkbox" /></th>
      <th>Size</th>
      <th>File</th>
    </tr>
  </thead>
  <tbody class="resizable">
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
    <tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr><tr>
      <td><input type="checkbox" /></td>
      <td>10Mb</td>
      <td>C:\Usabc.txt</td>
    </tr>
  </tbody>
</table>