String Replace Function in Flex

I'm not sure if this is a redundant function or not. I know that Flex String objects have a replace() method but as far as I can tell this only replaces the first match and not every match in a string.

Here is an actionscript function for flex which works the same as the php str_replace() function.

str_replace( needle, replacement, haystack ) in ActionScript

public function str_replace(needle:String, replacement:String, haystack:String):String
{
  var strArr:Array = haystack.split(needle);
  return strArr.join(replacement);
}

If this is a pointless function and there is an easier way to accomplish this built into flex I would love to hear about it. I looked over the language reference documents and couldn't find something.