var link1;

function ch_list( a ) 
{
  link1 = a;
  if(a == "list01"){
  list01.style.display = 'block';
  list02.style.display = 'none';
  list03.style.display = 'none';
  list04.style.display = 'none';
  document.main01.src='nyimages/newsqh/qh1_a.gif';
  document.main02.src='nyimages/newsqh/qh2_b.gif';
  document.main03.src='nyimages/newsqh/qh3_b.gif';
  document.main04.src='nyimages/newsqh/qh4_b.gif';
  }
  if(a == "list02"){
  list01.style.display = 'none';
  list02.style.display = 'block';
  list03.style.display = 'none';
  list04.style.display = 'none';
  document.main01.src='nyimages/newsqh/qh1_b.gif';
  document.main02.src='nyimages/newsqh/qh2_a.gif';
  document.main03.src='nyimages/newsqh/qh3_b.gif';
  document.main04.src='nyimages/newsqh/qh4_b.gif';
  }
  if(a == "list03"){
  list01.style.display = 'none';
  list02.style.display = 'none';
  list03.style.display = 'block';
  list04.style.display = 'none';
  document.main01.src='nyimages/newsqh/qh1_b.gif';
  document.main02.src='nyimages/newsqh/qh2_b.gif';
  document.main03.src='nyimages/newsqh/qh3_a.gif';
  document.main04.src='nyimages/newsqh/qh4_b.gif';
  }
  if(a == "list04"){
  list01.style.display = 'none';
  list02.style.display = 'none';
  list03.style.display = 'none';
  list04.style.display = 'block';
  document.main01.src='nyimages/newsqh/qh1_b.gif';
  document.main02.src='nyimages/newsqh/qh2_b.gif';
  document.main03.src='nyimages/newsqh/qh3_b.gif';
  document.main04.src='nyimages/newsqh/qh4_a.gif';
  }
}