Just another update

Task/Reverse-a-string/JavaScript/reverse-a-string.js

@@ -1,3 +1,18 @@
-var a = "cat".split("");
-a.reverse();
-print(a.join(""));   // tac
+//using chained methods
+function reverseStr(s) {
+  return s.split('').reverse().join('');
+}
+
+//fast method using for loop
+function reverseStr(s) {
+  for (var i = s.length - 1, o = ''; i >= 0; o += s[i--]) { }
+  return o;
+}
+
+//fast method using while loop (faster with long strings in some browsers when compared with for loop)
+
+function reverseStr(s) {
+  var i = s.length, o = '';
+  while (i--) o += s[i];
+  return o;
+}