Date: 2009apr24 Language: javaScript Q. Are javaScript parameters passed by reference or value? Can I control it? A. Objects are passed by reference and primitive types are passed by value. Primitives types are: Undefined, Null, Boolean, Number, and String. So... If you want to pass a primitive type by reference ==> wrap it in an object. If you want to pass an object by value ==> assign it to a temporary variable and pass that in.