Hackathon project regarding Twitter

I will be attending my first hackathon this upcoming weekend, and plan to create a Twitter-based Chrome extension. Basically, when someone wants to tweet or reply to something, and they click the 'tweet' button, it will open up a pop-up modal that asks them some questions about their tweet (so as to encourage them to be mindful about what they post). Within the modal, there will be a button that then publishes the tweet.

So, to sum it up, my modal will be an intermediary in the process of posting a tweet.

What technologies will be useful in implementing this? Specifically, how can I implement the feature in which someone clicks the tweet/reply button, and it opens up my web app's modal on the same screen? Correct me if I am wrong, but I think this is called event capture? Does this have anything to do with Web Intents?

Thanks!

Solution

I have done similar things on other sites. A high level overview of what you should try doing:

Find out how twitter sends tweets, the "tweet" button has a "js-send-tweets" class, I would start by investigating that. They probably have a piece of js listening to the button press.
Once you figured it out you can override that function by injecting your own script to the page after twitter's. This way when you press tweet your function will execute.
You should write your own logic in there then add twitter's function logic too which would conditionally execute based on the user's action.