Your code have more problems than the one in title.
This code is wrong in a subtile way:
var d = Math.random() * 100
...
if( d < 33) {
computerPick = "sizzors"
}
else if(d < 66){
computerPick = "rock"
}
else{
computerPick = "paper"
};
Odds are:
-sizzors 33%
-rock 33%
-paper 34%
This code is better:
var d = Math.random() * 3
...
if( d < 1) {
computerPick = "sizzors"
}
else if(d < 2){
computerPick = "rock"
}
else{
computerPick = "paper"
};