Reverse Integer

 1 var reverse = function(x) {
 2     var isNeg = false,
 3         res = 0,
 4         temp = 0;
 5 
 6     if (x < 0) {
 7         x = -x;
 8         isNeg = true;
 9     }
10 
11     while (x != 0) {
12         res = res * 10 + x % 10;
13         if (res > 2147483648) {
14             return 0;
15         }
16         x = Math.floor(x / 10);
17     }
18 
19     return isNeg ? -res : res;
20 };