//------------------------------
// initialize thumbnails on page load
window.onload = InitThumbs;

//------------------------------
// initialization
function InitThumbs()
{
         // apply onclick event ThumbClick() to all anchors within div#thumbbox
         [for each element in anchor array]
                 oThumbs[i].onclick = ThumbClick;
}

//------------------------------
// anchor click event handler
function ThumbClick()
{
         // handle event propagation
         ...

         // what to do when clicked
         body.className = this.id;

         // suppress linking to anchor href
         return false;
}