Data ranking in JS array __js

Implementing an Input array

var arr=new Array (40,20,30,50);

return results
(2,4,3,1)

That is 50 in the 40,20,30,50 ranked first, 40 row second, 30 of the row third, 20 row fourth. JS code is as follows

--Start

var arr = new Array (40,20,30,50);
function Sortbynumber (A, b) {return A.V-B.V}

function Mysort (AR) {
var ar_tmp = [], result = [];
for (x in AR) ar_tmp.push ({k:parseint (x) + 1, v:ar[x]});
Ar_tmp.sort (Sortbynumber);
For (i in ar_tmp) Result.push (AR_TMP[I].K);
return result;
}
Alert (Mysort (arr)); 2,4,3,1

--End

So we can send back the background program data, put to the front desk to do some ranking class calculation, reduce server pressure.