//Attach onclick events to radio buttons
function initForm() {
	var btnYr  = document.getElementById("timePeriodYr");
	var btnQtr = document.getElementById("timePeriodQtr");
	
	if(btnYr && btnQtr) {
	
		//Override browser behavior which will check 'Quarterly' radio button if it was previously selected but show annual data
		btnYr.checked = true;
	
		addEvent(btnYr,  "click", toggleDisplay);
		addEvent(btnQtr, "click", toggleDisplay);
		
	}
}

function toggleDisplay() {
	var btnYr  = document.getElementById("timePeriodYr");
	var btnQtr = document.getElementById("timePeriodQtr");
	var divYr  = document.getElementById("containerYr");
	var divQtr = document.getElementById("containerQtr");
	
	if(btnYr.checked) {
		divYr.style.display = "block";
		divQtr. style.display = "none";
	}
	else {
		divYr.style.display = "none";
		divQtr. style.display = "block";
	}
}

//Onload function
addEvent(window, "load", initForm);