Zooming a map

Hi everybody. I am newbie of action script. Can anybody help me dealing with the code below.
May I know what’s the mening stand for the setProperty… and from the if (Number(curZoom) == 0)

on (release, keyPress “<Left>”) {
if (Number(curxScroll)<Number(maxXpos)) {

setProperty("/map", _x, Number(getProperty("/map", _x))+Number(intScroll));

if (Number(curZoom) == 0) {

curxScroll = Number(curxScroll)+Number(intScroll);

} else if (Number(curZoom) == 1) {

curxScroll = Number(curxScroll)+Number(intScroll/2);

}

if (Number(curZoom) == 2) {

curxScroll = Number(curxScroll)+Number(intScroll/4);

} else if (Number(curZoom) == 3) {

curxScroll = Number(curxScroll)+Number(intScroll/8);

}

}

}

Thanks for kindly helping. Does anybody know where i able get the tutorial for map zooming?