var g_cur_page = 1;

function switch_page(i)
{
   i = parseInt(i);

   var last = 1;
   var elem = document.getElementById('page1')

   while (elem)
   {
      elem.style.display = 'none';
      last++;
      elem = document.getElementById('page' + last);
   } // while

   last--;
   g_cur_page += i;

   if (g_cur_page > last)
   {
      g_cur_page = 1;
   } // if
   if (g_cur_page < 1)
   {
      g_cur_page = 1;
   } // if

   if (g_cur_page == 1)
   {
      document.getElementById('prev').style.display = 'none';
      document.getElementById('next').style.display = 'block';
      document.getElementById('questions').style.display = 'none';
   } // if
   else if (g_cur_page == last)
   {
      document.getElementById('prev').style.display = 'block';
      document.getElementById('next').style.display = 'none';
      document.getElementById('questions').style.display = 'block';
   } // else if
   else
   {
      document.getElementById('prev').style.display = 'block';
      document.getElementById('next').style.display = 'block';
      document.getElementById('questions').style.display = 'none';
   } // else

   document.getElementById('page' + g_cur_page).style.display = 'block';
} // switch_page