Add event listener to DOM elements based on class,

I have a table, where each tr and td have only classes, I have a problem with selection of td element having the class I need. HTML:

<table>
 <tr class="data">
  <td class="cell">1</td>
  <td class="cell2"></td>
 </tr>
 <tr class="data">
  <td class="cell">2</td>
  <td class="cell2"></td>
 </tr>
</table>

When mouseover td with class="cell" I have to get text between td on which my mouse and do something with this. This should be done with pure JavaScript, without frameworks. I tried:

var cell = document.querySelector('.cell');

function callback(){ //do something }
cell.addEventListener('mouseover',callback(),false);

It doesn't work, or maybe I did mistakes?