Drilldown navigation menu by replacing divs
By dropping in some generic classes and data attributes like so:

&lt;div class="menuItem menuContainer first" data-target="second"&gt;Choose a Department&lt;/div&gt;
&lt;div class="menuContainer second"&gt;
    &lt;table class="Menu"&gt;
        &lt;tr&gt;
            &lt;td&gt;
                &lt;div class="menuItem third" data-target="seventh"&gt;Technology&lt;/div&gt;
            &lt;/td&gt;
            &lt;td&gt;
                &lt;div class="menuItem forth" data-target="sixth"&gt;Vehicles&lt;/div&gt;
            &lt;/td&gt;
        &lt;/tr&gt;
    &lt;/table&gt;
&lt;/div&gt;


menuContainer marks everywhere that's needs to be hidden or shown

menuItem marks everything links somewhere else in the menu

data-target is your link data

Now you can reduce your javascript to this:

$(document).ready(function () {
    $('.menuContainer').hide();
    $('.first').show();

    $('.menuItem').click(function () {
        var target = $(this).attr("data-target")
        if(target){
            $('.menuContainer').hide();
            $('.'+target).show();
        }
        return false;
    });
});