table, td {

border: 1px solid black;

}

<p>Click the button to add a new row at the first position of the table and then add cells and content.</p>

<table id="myTable">

<tr>

<td>Row1 cell1</td>

<td>Row1 cell2</td>

</tr>

<tr>

<td>Row2 cell1</td>

<td>Row2 cell2</td>

</tr>

<tr>

<td>Row3 cell1</td>

<td>Row3 cell2</td>

</tr>

<button type="button" onclick="myFunction()">Try it</button>

function myFunction() {

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

var row = table.insertRow(0);

var cell1 = row.insertCell(0);

var cell2 = row.insertCell(1);

cell1.innerHTML = "NEW CELL1";

cell2.innerHTML = "NEW CELL2";