JavaScript Iterator for IE and other browsers

This is just my proposal to add Iterator in Internet Explorer and other browsers too.

(function(){

 function Iterator(obj, name){
  // Iterator(obj) and new Iterator(obj) behaviour
  if(this instanceof Iterator){
   var i = 0,
    result = [],
    skip = false,
    key;
   for(key in obj){
    result[i++] = name ? key : [key, obj[key]];
    this[key] = undefined;
    if(!skip && (key == "constructor" || key == "toString" || key == "valueOf"))
     skip = true;
   };
   
   // solve IE problems
   for(var l = 0, arr = ["constructor", "toString", "valueOf"]; !skip && obj.hasOwnProperty && l < arr.length; l++){
    if(obj.hasOwnProperty(arr[l])){
     result[i++] = name ? arr[l] : [arr[l], obj[arr[l]]];
     this[arr[l]] = undefined;
    };
   };
   
   // add next method if any next in object
   this.next = function(){
    if(i === result.length)
     throw new StopIteration;
    else
     return result[i++];
   };
   
   // reset result "pointer"
   i = 0;
  }
  else
   return new Iterator(obj, !!name);
 };
 
 function StopIteration(message, fileName, lineNumber){
  this.message = message;
  this.fileName = fileName;
  this.lineNumber = lineNumber;
 };
 StopIteration.prototype = new Error;
 
 // global scope check
 if(!this.Iterator)
  this.Iterator = Iterator;
 if(!this.StopIteration)
  this.StopIteration = StopIteration;
})();


// test it!
var iter = Iterator({a:"b", next:"c", toString:"hello"}),
 output = [];
try{
 while(true)
  output.push(iter.next());
}
catch(err){
 if(err instanceof StopIteration)
  output.push("End of record");
 else
  output.push("Unknown error: " + err.description);
};
alert(output.join("\n"));

The best way to use them is with iter.next() method but you could use a for in loop too.
However, in latter case if the object has a next property, it will be overwrote by dynamic method but this problem apart, enjoy iterators :-)