Click to Call Asterisk SIP connect

I'm looking for someone who has had experience implementing Click-to-Call on a website that sends the request for a callback to an existing Asterisk/A2Billing Server. The scenario would be: 1. Visitor comes to my website 2. Visitor clicks on "Call me now" button 3. Visitor enters his/her phone number and presses "Submit" 4. Code activated upon pressing Submit, send a message to our Asterisk server instructing it to call back the visitor at the provided number That's it. Please tell me if you have actually implemented a feature like this that uses Asterisk in the backend.