Javascript Array br_search(target)

Array.prototype.br_search = function (target){ //The Array.prototype property represents the prototype for the Array constructor and allows you to add new properties and methods to all Array objects.
  var half = Math.floor(this.length / 2);
  if (target === this[half]){
    return half;/*w w  w . j a  v a  2 s  .  c om*/
  }
  if (target > this[half]){
    return half + this.slice(half,this.length).br_search(target);
  }
  else{
    return this.slice(0, half).br_search(target);
  }
};

l= [0,1,2,3,4,5,6];

console.log(l.br_search(5));