This page is part of a set of pages aimed at DWR developers. If this isn't you, then you probably want the documentation index.
The following notes are aimed at developers. Please do not try to understand how to use engine.js from these notes.
These notes supplied by Mike Wilson
As can be seen in the below matrix all tested platforms return the correct classname for all three object categories, except IE6 client-side objects that always return "Object".
PLATFORM BEHAVIOUR: IE6 FF1.5 Safari2.0 user-defined classes: class class class JavaScript core classes: class* class* class client-side/DOM classes: Object class class (* = all classes correct except Arguments->Object) PERFORMANCE IE6 FF1.5 Safari2.0 obj = new Superclass 8 usec 11 usec 3 usec obj = new Subclass 15 usec 18 usec 8 usec getObjectClassName(obj) 28 usec 75 usec 41 usec
This is a comparison that shows that querying object classnames has a performance of about the same order of magnitude as creating the objects. In the example the Subclass constructor calls the constructor of Superclass therefore the longer execution time for creating Subclass instances. Note that the IE6 and Safari2.0 numbers ARE comparable as FF1.5 has been used on both Windows and Mac platforms to balance the scores.
(* denotes deviations)
user-defined classes: IE6: function <class>
FF1.5: function <class>
Safari2.0: function <class>
native classes: IE6: function <class>
* Arguments: function Object
* Error subclasses: [object Error]
FF1.5: function <class>
* Arguments: function Object
Safari2.0: (Internal Function)
client-side/DOM classes: IE6: N/A (no constructor)
FF1.5: [<class>]
Safari2.0: (Internal Function)
user-defined classes: IE6: [object Object]
FF1.5: [object Object]
Safari2.0: [object Object]
native classes: IE6: [object <class>]
FF1.5: [object <class>]
* Arguments: [object Object]
* Error subclasses: [object Error]
Safari2.0: [object <class>]
* Error+subclasses [object Object]
client-side/DOM classes: IE6: [object Object]
FF1.5: [object <class>]
Safari2.0: [object <class>]