function pageSwitch(onpage, offpage)
{
	document.getElementById(offpage).style.display = 'none';
	document.getElementById(onpage).style.display = 'block';
}

function changeContents(flag)
{
	if (flag != undefined) {
		pageSwitch('content2', 'content1');
	} else {
		pageSwitch('content1', 'content2');
	}
}