function hide_answer(){
	divs = document.getElementsByTagName("div");
	for (i = 0; i < divs.length; i++) {
		if(divs[i].getAttribute('className') == "answer" || divs[i].getAttribute('class') == "answer"){
			divs[i].style.display ="none";
		}
	}
}

function dispSwitch(id){
	if(document.getElementById(id).style.display != "block"){
		document.getElementById(id).style.display ="block";
		divs = document.getElementsByTagName("div");
		for (i = 0; i < divs.length; i++) {
			if(divs[i].getAttribute('className') == "answer" || divs[i].getAttribute('class') == "answer"){
				divs[i].style.display ="none";
			}
		}
		document.getElementById(id).style.display ="block";
	}else{
		document.getElementById(id).style.display ="none";
	}
	return false;
}