Research And Implementation Of Supporting ActiveX Controls In Firefox

ActiveX controls are COM-based universal component, which can be used to create user interface easily by developer. Also, ActiveX controls provide classes for creating objects whose properties, methods and events can be applied. However, Firefox browser developed in Mozilla platform has not yet been able to run ActiveX controls, which limits its application in internet.In order to support ActiveX controls in Firefox, there are four problems that has to be solved, including how to create and initialize control objects, how to display and activate controls in-place in Firefox, how to enable JavaScript to invoke properties and methods of controls and how to capture events of controls and dispatch them to JavaScript. Based upon study on mechanism of running of ActiveX controls and various ways of expanding function of Firefox browser, npActiveX plug-in is designed and implemented and solves the problems mentioned above. After analyzing the time and methods of creating controls, it is decided that the information needed for creating and initializing controls is specified through HTML labels and their properties. Based on the study on the mechanism of plug-in and container part of OLE2.0, all the interfaces and methods that a container needed are implemented in npActiveX plug-in and the container works with controls well. Using XPCOM technology, JavaScript can access npActiveX plug-in so that it can indirectly access controls' properties and methods. npActiveX plug-in is able to capture events of controls and dispatch them to JavaScript, which is implemented based on the study of mechanism of events of controls.To enhance the safety of operation system, ActiveXManager add-on is designed and implemented. Users can operate this add-on to display CLSID, ProgID, version number and installation path of all controls and controls that has been supported by Firefox. Also, ActiveXManager can be used to enable or disable controls to run in Firefox. The user interface of this add-on is developed with XUL while the bottom function is provided by JavaScript and XPCOM. An installer using Overlay technology makes ActiveXManager add-on integrated within Firefox browser.Firefox displays configuration picture in the project of transformer substation well. The configuration picture is also used to test memory consumption and CPU occupancy rate of Firefox3.0 and IE7.0. After comparing and inducing the test result, it is concluded that in the case of opening certain number of web-pages, the system resource consumed by Firefox3.0 is as same as that of IE7.0. With more and more web-pages opened, the growth range of memory occupancy of Firefox3.0 is smaller than that of IE7.0.