Populate Tweet Box

Really simple little bit of code needed. I want to be able to be able to populate Twitter's Tweetbox with specified words by clicking buttons. You can see what I am trying to achieve by following the link below. By clicking on the input buttons you can see how these words are being entered into a text box. This is the same functionality I wish to achieve, but inserting it into the Tweetbox, not the text box. [login to view URL] Any problems just let me know. I would like to get a quick turnaround on this.