JSFiddle - React, Tailwind, and code Playground

by brymck

HTML

<table id="myTable">
 <tr>
  <td> 1 </td>
  <td> 2 </td>
  <td colspan="2"> 3 &amp; 4 </td>
 </tr>
 <tr>
  <td> 1 </td>
  <td> 2 </td>
 </tr>
 <tr>
  <td> 1 </td>
 </tr>
</table>

JavaScript

var table = document.getElementById("myTable");
var max = 0;

for (var i = 0, iLen = table.rows.length; i < iLen; i++) {
  var temp = 0;
  var cells = table.rows[i].cells;

  for (var j = 0, jLen = cells.length; j < jLen; j++) {
    temp += cells[j].colSpan;
  }

  if (temp > max) {
    max = temp;
  }
}
alert(max);