If else statements in JavaScript [on hold]

confitions: if amount is over100$, it'll be discounted about 20%. And,under 30, it cost additional 10$ .

I tried like this.　Plz tell me the rigjt code.

var list{[name:michel,amount:120 ;name:ann, amount:20

}

var michel =?
var ann =?

if(amount>100){

}

if(amount>30){

}
else(){

}