I got some questions!

hi guyz it’s me again sorry if I’m annoying still nooby cause i just started to learn AS!

my question is "is it possible to use the AS of flash 5 to flash 8?? would it be working??? or some will work but some will not ?? is there a site that i could study about the AS of flash8, so that i could replace the AS of flash5 to flash8… cause i have this code that won’t work in flash 8…
if someone can help me with this code… and make it advance in flash 8…
thank you! and advance GOD BLESS!!!

// ENTER RotateDisplayOrDrag() function here
function RotateDisplayOrDrag(whichPiece) {
if (Key.isDown(18)) {
_root[whichPiece]._rotation += 90;
} else if (Key.isDown(Key.SHIFT)) {
pieceNumber = whichPiece.slice(5);
} else {
startDrag(_root[whichPiece], false, 20, 20, 780, 580);
}
}