Javascript Array diff(arr)

Array.prototype.diff = function (arr) {

        // Merge the arrays
        var mergedArr = this.concat(arr);

        // Get the elements which are unique in the array
        // Return the diff array
        return mergedArr.filter(function (e) {
            // Check if the element is appearing only once
            return mergedArr.indexOf(e) === mergedArr.lastIndexOf(e);
        });/*from w w w .  j  a  v  a2s.c  o  m*/
};