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() {
@@ -257,22 +257,24 b' function processNewPost(post) {'
 }
 
 $(document).ready(function(){
-    initAutoupdate();
+    if ('WebSocket' in window) {
+        initAutoupdate();
 
-    // Post form data over AJAX
-    var threadId = $('div.thread').children('.post').first().attr('id');
+        // Post form data over AJAX
+        var threadId = $('div.thread').children('.post').first().attr('id');
 
-    var form = $('#form');
+        var form = $('#form');
 
-    var options = {
-        beforeSubmit: function(arr, $form, options) {
-            showAsErrors($('form'), gettext('Sending message...'));
-        },
-        success: updateOnPost,
-        url: '/api/add_post/' + threadId + '/'
-    };
+        var options = {
+            beforeSubmit: function(arr, $form, options) {
+                showAsErrors($('form'), gettext('Sending message...'));
+            },
+            success: updateOnPost,
+            url: '/api/add_post/' + threadId + '/'
+        };
 
-    form.ajaxForm(options);
+        form.ajaxForm(options);
 
-    resetForm(form);
+        resetForm(form);
+    }
 });