24点终结者(javascript)[1]

<script language="javascript" >
function tdisoper(f0,f1,f2,f3)
{
this[0]=f0;
this[1]=f1;
this[2]=f2;
this[3]=f3;
}
disoper=new tdisoper("-","+","/","*");

function oper(f,m,n)
{
if (f==3) return(m*n);
if (f==2) return(m/n);
if (f==1) return(parsefloat(m)+parsefloat(n));
if (f==0) return(m-n);
}

function tb(i1,i2,i4,i8)
{
this[1]=i1;
this[2]=i2;
this[4]=i4;
this[8]=i8;
}

function valid(f)
{
n=f.count1.options[f.count1.selectedindex].value;
if (isnan(f.a1.value)){alert("必须输入整数！");    f.a1.focus();    return(false);}
if (isnan(f.a2.value)){alert("必须输入整数！");    f.a2.focus();    return(false);}
if (isnan(f.a4.value)){alert("必须输入整数！");    f.a4.focus();    return(false);}
if (isnan(f.a8.value)){alert("必须输入整数！");    f.a8.focus();    return(false);}
b=new tb(f.a1.value,f.a2.value,f.a4.value,f.a8.value);
k=0;
f.text.value="";

for (i1=1;i1<=8;i1*=2)
 for (i2=1;i2<=8;i2*=2)
   for (i3=1;i3<=8;i3*=2)
     for (i4=1;i4<=8;i4*=2)
       {
        if ((i1|i2|i3|i4)!=0xf) continue;
          for (f1=0;f1<=3;f1++)
            for (f2=0;f2<=3;f2++)
              for (f3=0;f3<=3;f3++)
                  {