Responds "Yes" to

  9007199254740990, 9007199254740991, 9007199254740992

but "No" to

  9007199254740991, 9007199254740992, 9007199254740993

Presumably this is due to how Javascript handles integers, i.e. it uses the integer part of a float64, to wit

  > parseInt('9007199254740992')
  9007199254740992
  > parseInt('9007199254740993')
  9007199254740992

Edit: I think this is the code that actually reads the numbers the user enters, see [0]

  function l(){
      var a=h.exec(m[1]),f=null,g=null,n=null;
      return a&&(null!==a[1]&&a[1]&&(f=parseInt(a[1],10)),
          null!==a[2]&&a[2]&&(g=parseInt(a[2],10)),
          null!==a[3]&&a[3]&&(n=parseInt(a[3],10))),
      new e(f,g,n)
  }

Edit(2): Actually, I'm not so sure that's the correct code at all. They NYT game is capable of parsing floats correctly (e.g. it accepts 1.1, 1.2, 1.3 as a "Yes") so it's not just using parseInt.

[0] http://a1.nyt.com/assets/interactive/20150612-151638/js/foun...