jQuery or Javascript solution to make a vertical navigation sidebar like blogger dynamic view

you can use both but in jQuery you can put your condition if this condition is done you can add style to the div/span you want to scroll if you have this div

<div id="tableTag" style="height:120px;">
   <table>
      <tr>
         <th>caption1</th>
         <th>caption2</th>
         .
         .
         etc
      </tr>
   </table>
</div>

i prefer using JQuery in this case because it is easy to control and easy to add styles and attributes :

// get Data
// make your condition :
if(rowCount >= 10)
{
   $("#tableTag").css('overflow', 'auto');
}