CRM 2011 hiding one related link from entity left nav "Documents", "Campaign"

This Javascript hides one related link

function hideNavItem(navItem) {
     Xrm.Page.ui.navigation.items.forEach(function (item, index) {
         var itemLabel = item.getLabel();
         if (itemLabel == navItem) {
             item.setVisible(false);
         }
     });
 }

hideNavItem("Relationships");

You can hide Activities by:

hideNavItem("Activities");