Twitter listeners stopped working suddenly



I integrated twitter tweet button into my wordpress plugin, And i set a listener :'tweet', function(){
alert('You Tweeted It!');

This listener shows an alert once the tweet is done, The plugin worked for me for 3 days, At the day four, With no changes on code, An error message started to appear, And seems like the listener stopped working, I dont see the alert anymore.

Google Chrome shows an error in the console : Uncaught TypeError: undefined is not a function widgets.js? =1483(number):44

So something is wrong with the line 44, Does anyone have any idea what happened? As i didnt touch the code and this is happening suddenly.