var pdiv = 'food1';
function show(cdiv) {
  if (pdiv) {
    document.getElementById(pdiv).style.display='none';
    document.getElementById('li' + pdiv).className='';
  }
  pdiv = cdiv;
  document.getElementById(cdiv).style.display='';
  document.getElementById('li' + pdiv).className='current';
}

function sf(){document.f.food.focus();}