function tweet() {
	var login  = 'ecoichi'; // ← bitly に登録したユーザ名
	var apiKey = 'R_67364f92c8bf611d5fc8b4be5b02064d'; // ← bitly API Key
	bitly = 'http://api.bit.ly/shorten' 
	    + '?version=2.0.1&format=json&callback=callback'
	    + '&login=' + login
	    + '&apiKey=' + apiKey + '&longUrl=';
	var script = document.createElement('script');
	script.type = 'text/javascript';
	script.src = bitly + encodeURIComponent(location.href) ;
	document.body.appendChild(script);
}

function callback(bitlyResponse) {
	var ind = document.title.indexOf(' ');
	var title = document.title.slice(0,ind);
	var url = 'http://twitter.com/home/?status=' 
	    + encodeURIComponent(
	         'エコチャレなう 「'+title + '」 ' 
	           + bitlyResponse.results[location.href]['shortUrl']
	      );
	location.href = url;
}