Use thread autoupdate only if websockets available

boards/static/js/thread_update.js

@@ -124,7 +124,7 b' function isPageBottom() {'
 }
 
 function initAutoupdate() {
-    connectWebsocket()
+    connectWebsocket();
 }
 
 function getReplyCount() {
@@ -257,6 +257,7 b' function processNewPost(post) {'
 }
 
 $(document).ready(function(){
+    if ('WebSocket' in window) {
     initAutoupdate();
 
     // Post form data over AJAX
@@ -275,4 +276,5 b' function processNewPost(post) {'
     form.ajaxForm(options);
 
     resetForm(form);
+    }
 });