I found the following example to be extremely confusing:

  a = 10  
  b = 5 > a > 30

When I thought about it after seeing what it compiles to:

  var a, b;

  a = 10;  
  b = (5 > a && a > 30); 

I couldn't see how that statement could be true because a cannot be less than 5 while also be greater than 30.

Range checking I would assume would be:

  b = 5 < a > 30