TActiveForm = class(TCustomActiveForm)
class PASCALIMPLEMENTATION TActiveForm : public Vcl::Forms::TCustomActiveForm
TActiveForm is the base class for a VCL Form exposed as an ActiveX control. TActiveForm represents a form that is created by a class factory (in Delphi) or using the Active Template Library (C++) and used as an ActiveX control in ActiveX host applications.
A TActiveForm object is used to create a form ActiveX control that can be displayed and run from within Web browsers.
Note: In Delphi applications, this object is created by TActiveFormControl. It is a descendant of this class that you design in the Form Designer when you create an ActiveForm.