function binomial(n, k) {  
     if ((typeof n !== 'number') || (typeof k !== 'number'))   
  return false;   
    var coeff = 1;  
    for (var x = n-k+1; x <= n; x++) coeff *= x;  
    for (x = 1; x <= k; x++) coeff /= x;  
    return coeff;  
}  
  
console.log(binomial(8,3));  
console.log(binomial(10,2));