Added "heartbeat" for update throttling.

guacamole/client/web/javascript/guacamole.js

@@ -540,7 +540,27 @@ function VNCClient(display) {
             handler(parameters);
 
     }
-        
+
+
+    function sendReady() {
+
+        // Start heartbeat signal
+        var heartbeat = new XMLHttpRequest();
+        heartbeat.open("GET", "ready");
+
+        heartbeat.onreadystatechange = function() {
+
+            if (heartbeat != null && heartbeat.readyState >= 2) {
+                heartbeat = null;
+                setTimeout(sendReady, 50);
+            }
+
+        };
+
+        heartbeat.send();
+
+    }
+
 
     this.connect = function() {
 
@@ -555,6 +575,7 @@ function VNCClient(display) {
         var message = new GuacamoleMessage(connect_xmlhttprequest.responseXML);
         if (!message.hasErrors()) {
             setState(STATE_WAITING);
+            sendReady();
             handleResponse(makeRequest()); // Start stream if connection successful
         }
         else