title: How to build a single sign-on application (email and pass)?
body: <p>I want to build a single login interface (with Angular) which should be a kind of stand alone, so that it can be used and embedded from/on any page.</p>
  
  <p>E.g. a customer can embed it on his index page as over layer and the code/functions should be will passed from a JavaScript API and build the the UI and the connection.</p>
  
  <p>I'am thinking about a concept like single sign-on application which allows users to interact on other websites through their account on Facebook. 
  Something like Facebook connect.</p>
  
  <p>What's the best approach to reach this? Preferred technology is Angular2, Angular4</p>