Adding rows and columns to an HTML table

Let's say we have some HTML table - #table. Let's learn how to add new rows and columns to it.

Adding rows

Adding rows is not difficult: you need to create tr, and then run a loop that will add the desired number of cells to this row (let's say 3):

javascriptlet table = document.querySelector('#table');

let tr = document.createElement('tr');

for (let i = 1; i <= 3; i++) {
  let td = document.createElement('td');
  tr.appendChild(td);
}

table.appendChild(tr);

Adding columns

But with adding columns, it’s a little more complicated: you need to run a loop that will go through all the table rows and add a new cell to each row:

javascriptlet trs = document.querySelectorAll('#table tr');

for (let tr of trs) {
  let td = document.createElement('td');
  tr.appendChild(td);
}

html<table id="table">
  <tr>
    <td></td>
    <td></td>
  </tr>
  <tr>
    <td></td>
    <td></td>
  </tr>
</table>

csstd {
  width: 50px;
  height: 50px;
  border: 1px solid black;
}