document.observe("dom:loaded", function() {
    $$('a.htab').each(function (i) {
        i.observe('click', function (e) {
            var name = i.id;
           
            // Remove active from everything
            $$('a.htab').each(function (j) {
                j.removeClassName('active');
            });
            
            i.addClassName('active');
            
            // Hide all panels
            $$('.panel').each(function (j) {
                j.removeClassName('active');
            });
            
            $(name + '_panel').addClassName('active');
            
            Event.stop(e);
        });
    })
});