JavaScript EXPOCIC

var vetor=new Array(20);
for(i=0;i<20;i++){
    vetor[i]=0;
}
var start=0;
var plays=0;
var cora=0;
var wins=0;
var lose=0;
var bomba=0;
function sorteio(t,q){
    for(i=1;i<=parseInt(q);i++){
        do{
            u=Math.floor((Math.random() * 19) + 1);
        }while(vetor[u]!=0);
        vetor[u]=parseInt(t);
    }
}
function depois(){
    for(i=0;i<20;i++){
        document.getElementById('t' + i).innerHTML='&nbsp;';
        document.getElementById('t' + i).className="";
        vetor[i]=0;
    }
    document.getElementById('w1').innerHTML=3;
    document.getElementById('w2').innerHTML=0;
}

function clica(){
    depois();
    start=1;
    sorteio(1,3);
    sorteio(2,6);
    document.getElementById('tabela').style="background-color: #4dc3ff;";
    document.getElementById('butao').disabled="disabled";
}
function ok(){
    depois();
    document.getElementById('butao').disabled="";
    bomba=0;
    cora=0;
    document.getElementById('w1').innerHTML=3;
    document.getElementById('w2').innerHTML=0;
    document.getElementById("butao").style.visibility="visible";
}
function rt(x){
    if(start==1){
        if(document.getElementById('t' + x).innerHTML=='&nbsp;'){
            plays++;
            document.getElementById('t' + x).className="escolha";
            switch (vetor[x]) {
                case 1: document.getElementById('t' + x).innerHTML='&#10084;';
                        document.getElementById('w1').innerHTML=parseInt(document.getElementById('w1').innerHTML)+1;
                        cora++;
                    break;
                case 2:document.getElementById('t' + x).innerHTML='&#128163;';
                        document.getElementById('w2').innerHTML=parseInt(document.getElementById('w2').innerHTML)+1;
                        document.getElementById('w1').innerHTML=parseInt(document.getElementById('w1').innerHTML)-1;
                        bomba++;
                    break;
            }
            if(cora==3){
                alert("ganhou");
                ok();
                start=0;
            }
            if(bomba==6 || parseInt(document.getElementById('w1').innerHTML)==0){
                alert("perdeu");
                ok();
                start=0;
            }
        }
    }
    else
        if(start==0){
            alert("Tem de começar o jogo!");
        }
}