function relative_time(time_value) {
	var parsed_date = Date.parse(time_value);
	var relative_to = (arguments.length > 1) ? arguments[1] : new Date();
	var delta = parseInt((relative_to.getTime() - parsed_date) / 1000);
	if(delta < 60) {
		return '(1分以内)';
	} else if(delta < 120) {
		return '(1分前)';
	} else if(delta < (45*60)) {
		return '(' + (parseInt(delta / 60)).toString() + '分前)';
	} else if(delta < (90*60)) {
		return 'about an hour ago';
	} else if(delta < (24*60*60)) {
		return '(約' + (parseInt(delta / 3600)).toString() + '時間前)';
	} else if(delta < (48*60*60)) {
		return '(昨日)';
	} else {
		return '(' + (parseInt(delta / 86400)).toString() + '日前';
	}
}
function twitterCallback(obj) {
	var id = obj[0].user.id;
	document.getElementById('my_twitter_status').innerHTML = obj[0].text;
	document.getElementById('my_twitter_status_time').innerHTML = relative_time(obj[0].created_at);
}