ActiveX is not supported on the Mac. JavaScript doesn't parse ActiveX content.
Web pages and web applications written in ActiveX will only run on Internet Explorer on Windows. When coding with ActiveX, you're pretty much accepting that the only people that will be able to use the ActiveX portions are those running Internet Explorer under Windows. Using ActiveX to try and create cross-browser and cross-platform applications is a horrible idea. Only use ActiveX if 100% of your customer base uses Windows and Internet Explorer.