Punny 0 Newbie Poster

Can I use JavaScript on MYSQL? If so, do I keep using the old JS or move on to wxJavaScript? What is wxJS? I read it somewhere on-line and never fully understand any of it.

Is studying PHP worth it after I finish doing JS? My goal is to make a replica of YouTube,Facebook, and BlogTV that's what I'm aiming for.

Can JS be compatible with smart phones? If not, then what program? it has to be both computer and phones. Someone told me about ColdFusing, what is it?