MergeSort.js

// require Merge.js

var MergeSort = function(A,p,r) {
    if (p < r) {
        var q = Math.floor(r-p);
        var left = MergeSort(A,p,q);
        var right = MergeSort(A,q+1,r);
        return Merge(A,p,q,r);
    }
    return A;
};

var ar=[null,6,7,8,9,1,2,3,4,5];

console.log(MergeSort(ar,1,9));