Javascript Array numberOfOccurrences(values)

/* numberOfOccurrences //from ww w .  j a  v a 2  s .  c o  m

The numberOfOccurrences function must return the number of occurrences of an element in an array.

var arr = [0,1,2,2,3];
arr.numberOfOccurrences(0) === 1;
arr.numberOfOccurrences(4) === 0;
arr.numberOfOccurrences(2) === 2;
arr.numberOfOccurrences("a") === 0;


*/

Array.prototype.numberOfOccurrences = function(values) {

var tracker = 0;

    for(var i = 0; i < this.length; i++)
    {
        if (this[i]== values){

            tracker++;
        }
    }
    
    console.log(tracker);
};


var arr = [0,1,2,2,3];
arr.numberOfOccurrences(0);
arr.numberOfOccurrences(4);
arr.numberOfOccurrences(2);
arr.numberOfOccurrences("a");