<table>
<tr> <td>1</td><td>2</td><td>3</td> </tr>
<tr> <td>4</td><td>5</td><td>6</td> </tr>
<tr> <td>7</td><td>8</td><td>9</td> </tr>
.
.
.
<tr> <td>n</td><td>n+1</td><td>n+2</td> </tr>
</table>

[CSS]<style>
tr.On{
    background:#EDEDED;
    color: #3D3D3D;
    padding: 4px;
    vertical-align: top;
}
tr.Out{
    background:#f9f9f9;
    color: #3D3D3D;
    padding: 4px;
    vertical-align: top;}
tr.On2{
    background:#ffffff;
    color: #3D3D3D;
    padding: 4px;
    vertical-align: top;
}

</style>[/CSS]

[JavaScript]<script type="text/javascript">//funkcja podświetlanie
//<![CDATA[
mouseHighlight = function(){
  var i, tr = document.getElementsByTagName('tr');
  for(i = 0; i<tr.length; i++){
    if(tr[i].className=='Out'){
      tr[i].onmouseover = function(){this.className = 'On'};
      tr[i].onmouseout = function(){this.className = 'Out';

      }
    }
    tr[i].onclick = function(){
      this.className = 'On2';
      document.getElementById("nnn").innerHTML=i;
    }    
  }
}
window.onload = mouseHighlight;
//]]>
</script>[/JavaScript]