var current = null;

function goshow (myshow)
{
  if ( current == null ) {
  myshow.style.display = 'block';
  current = myshow;
  }
  else {
  gohide(current);
  myshow.style.display = 'block';
  current = myshow;
  }
}
function gohide (myhide)
{
  myhide.style.display = 'none';
}
function changeclassname(name)
{
	document.getElementById().class="caja1";
}