function revealAnswer(framename,url)
{
 var viewer = document.getElementById(framename,url);
 viewer.style.margin = '2px;'
 viewer.style.display = 'block';
 viewer.src=url;
}

function clearFrame(framename)
{
 var viewer = document.getElementById(framename);
 if (viewer.style.display == 'block') viewer.style.display  = 'none';
 if (viewer.style.visibility == 'visible') viewer.style.visibility = 'hidden';
}



function showAnswer(framename)
{
 if (answer) 
 {
  var viewer = document.getElementById(framename);
  viewer.style.visibility = 'visible';
  viewer.style.margin = '2px';
  viewer.src='../play/' + answer + '.html';
 }
}