<html><head><script>function changeContent(){var x=document.getElementById('myTable').rows[0].cells;x[0].innerHTML="NEW CONTENT";}</script></head><body><table id="myTable" border="1"><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></table><form><input type="button" onclick="changeContent()" value="Change content"></form></body></html>