// 獲取文章數量的封裝對象
var socialGetter = (function() {
/* JSONP: 獲取腳本的工具函數 */
function injectScript(url) {
var script = document.createElement('script');
script.async = true;
script.src = url;
document.body.appendChild(script);
}

return {
getFacebookCount: function(url, callbackName) {
injectScript('https://graph.facebook.com/?id=' + url + '&callback=' + callbackName);
},
getTwitterCount: function(url, callbackName) {
injectScript('http://urls.api.twitter.com/1/urls/count.json?url=' + url + '&callback=' + callbackName);
}
};
})();

// 回調方法
function twitterCallback(result) {
result.count && console.log('The count is: ', result.count);
}
function facebookCallback(result) {
result.shares && console.log('The count is: ', result.shares);
}

// 調用
socialGetter.getFacebookCount('http://davidwalsh.name/twitter-facebook-jsonp', 'facebookCallback');
socialGetter.getTwitterCount('http://davidwalsh.name/twitter-facebook-jsonp', 'twitterCallback');