Edit in JSFiddle

function alertEvent()
{
    alert('Event Added');
}
var c=document.getElementById('t').getElementsByTagName('td');
for (x=0;x<c.length;x++)
{
    c[x].onclick=alertEvent;
}

<a href='http://z54.com' target='_blank'>Adding Event Listern Example</a>
<table id='t'><tr><td>cell1</td><td>cell2</td><td>cell3</td></tr>
<tr><td>cell4</td><td>cell5</td><td>cell6</td></tr>
<tr><td>cell7</td><td>cell8</td><td>cell9</td></tr></table>

table#t tr td
{
cursor:pointer;
}