//visible answer global var.
visibleAnswer = -1;

//on load
YAHOO.util.Event.addListener(window, 'load', init);
function init(e)
{
	//foreach answer
	var answers = YAHOO.util.Dom.getElementsByClassName('answer');
	for(var i=0; i<answers.length ;i++)
	{
		//hide answer
		answers[i].style.display="none";
	}
	
	//assign submit event handler to all questions and hover style.
	var questions = YAHOO.util.Dom.getElementsByClassName('question');
	for(var i=0; i<questions.length ;i++)
	{
		YAHOO.util.Event.addListener(questions[i], 'click', clickedQuestion);
	}	
}

function clickedQuestion(e)
{
	//get question id
	var id = this.id.substring(1,this.id.length);
	
	//hide visible answer
	if(visibleAnswer != -1)
	{
		document.getElementById('a'+visibleAnswer).style.display = 'none';
	}
	
	//show answer
	if(visibleAnswer!=id)
	{
		document.getElementById('a'+id).style.display = 'block';
		visibleAnswer = id;		
	}
	else
	{
		visibleAnswer = -1;		
	}
}