Topic: Asynchronous For-In Loops in Firefox

AsyncLooper = 
   {
      go:
         function(obj,iCallback,eCallback) {
            AsyncLooper.loop(obj,iCallback,eCallback,Iterator(obj));
         },
      loop:
         function(o,i,e,I) {
            var prop;
            for(var counter=0;counter<21;counter++) {
               try { // only way to check if there aren't any more properties
                  prop=I.next();
               } catch (e) { // if no more properties
                  return e(o)
               }
               i(o,p[0],p[1]);
            }
            window.setTimeout(AsyncLooper.loop,1,o,i,e,I);
         }
   };

// And a usage example:
myPointlessObject = {a:123,b:456,c:789,e:345,d:012};
STRING="myPointlessObject == "+myPointlessObject.toSource();
AsyncLooper.go(myPointlessObject,
   function(o,n,v) {
      STRING+="\nmyPointlessObject['"+n+"'] == "+v
   },
   function() {
      alert(STRING);
   }
);

// Assume that myIterator is an Iterator.
for(i in myIterator) {
   break;
}
for(i in myIterator) {
   // even if the break statement
   // above ran before the Iterator
   // was "finished", this code will
   // never run...
}
myIterator.next();
// and calls to its next() method
// cause StopExceptions.