Is it possible, using Twitter's Web Intents, to have a link that when clicked :
- Opens a popup to send a tweet containing the link I have chosen (no problem so far, I have tried that and it works)
- Then, once the tweet is sent, calls a js or php script ?
Twitter's Tweet Web Intent doesn't provide this functionality. You'd have to build a solution using either the REST or Streaming APIs. Even that would only work if the user's Tweets are public, or if they give you read access to their timeline.