var all_open=false;
function answer(answerElementId){
var ae = document.getElementById(answerElementId);
if ( ae.style.display!='block'){
   ae.style.display='block';
} else {
   ae.style.display='none';
}
}

function view_all(){
all_open=!all_open;
var dval = all_open?'block':'none';
aels = document.getElementsByTagName('div');
s='';
var i=0;
for(i=0;i<aels.length;i++){
 var n=aels[i].getAttribute('id');
 if ( n!=null && n.indexOf('a')==0 ){
  aels[i].style.display=dval;
 }
}
var button_text=all_open?'close all':'view all';
var btn=document.getElementById('vubtn');
var td = document.createTextNode(button_text);
btn.replaceChild(td,btn.firstChild);

}