about JS VS VBScript VS Dart

You can take it as a joke since this is not a proper comparison of these web programming languages.

                                JS      Dart    VBScript
types                           √       √       sort of
getters and setters             √       √       √
immutable objects               √       √       √
prototypal inheritance          √
simulated classes               √
"real" classes                          √       √
closures                        √       √       
weakly bound to JS                      √       √
obtrusive for JS (global)       may be  √       √
obtrusive for JS (prototypes)   may be  √
operator overload                       √
cross browser                   √
real benefits for the Web       √       ?       ?

If you are wondering about JS types, we have both weak type and strong type, e.g. Float32Array.
When StructType and ArrayType will be in place then JS will support any sort of type.