function addClickHandlers()
{
    var allDivs = document.getElementsByTagName("div");
    for (var i=0; i<allDivs.length; i++)
    {
        if (allDivs[i].className == "product_thumb")
        {
            if (allDivs[i].addEventListener)
            {
                allDivs[i].addEventListener("click", function(evt) {
                    window.location.href = evt.currentTarget.getElementsByTagName("a")[0].href;
                }, false);
            }
            else
            {
                allDivs[i].attachEvent("onclick", function() {
                    window.location.href = window.event.srcElement.parentNode.getElementsByTagName("a")[0].href;
                } );
            }
        }
    }
}

if (window.addEventListener)
{
    window.addEventListener("load", addClickHandlers, false);
}
else
{
    window.attachEvent("onload", addClickHandlers);
}