youtube.LiveSearch = Class.create({
    /**
     * コンストラクタ
     */
    initialize: function(keyword) {
	this.previousKeyword = keyword;
    },
    /**
     * 前回のキーワードと異なればJSONPで検索
     */
    search: function(keyword, callback) {
	if (this.previousKeyword != keyword) {
	    var url = 'http://gdata.youtube.com/feeds/videos?' + 
		      'vq=#{keyword}&alt=json-in-script&callback=#{callback}&max-results=9';
	    url = url.interpolate({keyword:  encodeURIComponent(keyword),
				   callback: callback});

	    jsonp = new JSONscriptRequest(url);
	    jsonp.buildScriptTag();
	    jsonp.addScriptTag();
	    this.previousKeyword = keyword;
	}
    }
});