function showAnswer(answerid) {
  answer = document.getElementById(answerid);
  // alert(answer.style.display);
  
  if (answer.style.display == "none" || answer.style.display == "") {    
    divs = document.getElementsByTagName("DIV");

    for (i = 0; i < divs.length; i++) {
      if (divs[i].className == "answer") {
        divs[i].style.display = "none";
      }
    }
    
    answer.style.display = "block";  
  }
  else {
    answer.style.display = "none";
  }
}