The questions you are asking indicate that you will have along learing curve.
animated gifs are mage up of a number of images.
Javascript can do this but speed can become an issue.
also shapes can be drawn and animated with javscript.
code complexity and size become issues as well as speed.
the page I used featured dials.
have a look at
http://www.vicsjavascripts.org.uk/An...alogueDial.htm
to guage the complexity
but I think that Java or Flash may be better tools