When is an applet not an applet?

Not everything that looks like a Java applet is one. Some web pages for Microsoft Internet Explorer use Microsoft's ActiveX controls and plug-ins. Plug-ins for Firefox typically employ Mozilla's XUL dialect of XML, together with related technologies. In addition, some sites create applet-like functionality with Macromedia Flash or Shockwave.
However, while solutions with these tools are sometimes easier to develop than Java applets, they generally either lack the cross-browser appeal, or else require that the user download a proprietary plug-in.