gistfile1.js

// Only one closure is created here - i.e. when one of these functions is returned from within anonymous-outer one. 
// That returned function will be part of the closure and have access to [[Scope]] of anonymous-outer one.  
// The returned function is the only Function object that's being created. 
// Function expressions from other blocks are never reached and so are never created 

var globalEval = (function(){
  if (window.eval) {
    return function(s){ window.eval(s) }
  }
  else if (window.execScript) {
    return function(s){ window.execScript(s) }
  }
  return function(s){
    // use script insertion
  }
})();