title: Javascript: How is it possible to get a mobile phone number of a user?
body: <p>I was on facebook and clicked a "click bait" website about top 10 most expensive dogs. a riveting read as you all will agree. after leaving the website, I got a text message saying i have subscribed to best dog facts.</p>
  
  <p>How is this even possible? Assume i clicked something on the website that gave consent, is there an actual javascript api that can get a number/or send a text message to a mobile device?</p>
  
  <p>More information:
  the website was loaded in facebook apps built in browser  (some exploit there?)
  my phone is a samsung galaxy s7, not rooted</p>
  
  <p>any ideas would be great as every search so far has yielded no results pointing towards this actually being possible. yet i just experienced it.</p>