var arr = [2, 1, 3, 6, 4, 7, 5];
function xz(arr){
for (var i = 0; i < arr.length - 1; i++) {
for (var j = i + 1; j < arr.length; j++) {
if (arr[i] > arr[j]) {
var t = arr[i];
arr[i] = arr[j];
arr[j] = t;
}
}
}
return arr
}

console.log(xz([6,5,4,3,2,1]))
console.log(xz([4,5,4,12,21,1]))
console.log(xz([11,5,45,3,6,90]))