var exclude; // set the variable exclude so that it can be accessed globally
      /* overides the effects of the changeColor function (on mouse over) */
      function hover(id) {
        if(exclude) {
          if(id != exclude) {
            var object = document.getElementById(id);
            object.style.color = '#3F5F85';
          }
        }
      }
      /* overides the effects of the changeColor function (on mouse out) */
      function unhover(id) {
        if(exclude) {
          if(id != exclude) {
            var object = document.getElementById(id);
            object.style.color = 'white';
          }
        }
      } 
      /* changed the colour of all the nav items, highlighting the selected link */
      function changeColor(id) {
        exclude = id;
        var excludeObject = document.getElementById(id);
        for(i=1;i<=12;i++) {
          if(id != 'a'+i) {
            var object = document.getElementById('a'+i);
            object.style.color = 'white';
          }
        }
        excludeObject.style.color = '#3F5F85';
      }
      /* ajax function that loads the content into the div with id called 'main' */
      function loadContent(url) {
        new Ajax.Updater('main', url, {asynchronous:false, method:'get'}); return false;
      }