What\'s all this business about Flash, Flex, Adobe Air, Java FX and Silverlight? Why would I choose one over the other? and what happened to Java Applets and ActiveX controls?>
Sounds like you need to fire up Google and do a little research and reading. Start with "rich Internet application" or "RIA", or simply enter those terms and enjoy.
Consider the first three to be synonyms; JavaFX is the Sun offering; Silverlight is Microsoft's entry.
Nothing "happened" to applets or ActiveX controls, they're both still with us. They're a bit dated and fallen out of favor. Applets had their heyday when teapots first danced on the Web; ActiveX controls have some security issues.
Laszlo appears to be the inspiration for Flex, according to this.