title: Scan Javascript for browser compatibility
body: <p>Is there a tool out there to scan my Javascript code for functions that may not be present in all browsers? </p>
  
  <p>My library is completely non-UI, so I don't care about how something is "displayed". What I'm looking for is something like in the Javascript MDN from Mozilla. For example, for Array.prototype.indexOf, they warn that it's a recent ECMAScript addition that is not present in all browsers (and typically provide a stub). 
  What I'm looking for is a tool that'd list the functions in my code that would fall into this category.</p>