function tidy(dirty){
    return unescape(dirty.replace(/\+/gi, " "));
}

var displayedAnswer=-1;

function showAnswer(index){
    var ans=null;
    if(displayedAnswer>=0){
        ans = top.document.getElementById("answer"+displayedAnswer);
        ans.style.visibility="hidden";
    }
    
    ans = top.document.getElementById("answer"+index);
    ans.style.visibility="visible";
    displayedAnswer=index;
}

function dirty(tidy){
    return encodeURIComponent(tidy.replace(/\+/gi, " "));
}