Binomial coefficient in javascript

BinomialCoefficient.js

// Binomial coefficient
// Credits: github.com/jgferreiro

examples();

function examples() {
  var a, b; // numerator and denominator of our coeffiecient
  
  a = 2; b = 1;
  console.log('Binomial for a = ' + a + " and b = "+ b + ' is ' + binomialCoefficient(a, b));
  
  a = 18; b = 2;
  console.log('Binomial for a = ' + a + " and b = "+ b + ' is ' + binomialCoefficient(a, b));
  
}

// Returns the binomial coefficient
// where a is the total set of posibbilites
// and b is the number of combinatios we're interested in

function binomialCoefficient(a, b) {
  numerator = fact(a);
  denominator = fact(a-b) *  fact(b);
  return numerator / denominator;
}

// Factorial function.
function fact(x) {
   if(x==0) return 1;
   return x * fact(x-1);
}