Fix the typong tests not working properly

www/common/TypingTests.js

@@ -33,7 +33,7 @@ define(function () {
         interval = setRandomizedInterval(function () {
             cb();
             try {
-                el.replaceData(j, 0, input.charAt(i));
+                el.replaceData(Math.min(j, el.length), 0, input.charAt(i));
             } catch (err) {
                 errors++;
                 if (errors >= max_errors) {

www/common/netflux-client.js

@@ -133,7 +133,7 @@ const onMessage = (ctx, evt) => {
         return;
     }
     if (msg[2] === 'PING') {
-        msg[1] = 'PONG';
+        msg[2] = 'PONG';
         ctx.ws.send(JSON.stringify(msg));
         return;
     }