chat: Prevent user from submitting a 2nd message before his 1st is re…

…ceived.

Some users reported that mod/chat was silently dropping some messages. The
user's browser may not be able to keep up with the rate at which he submits
chat messages. This update keeps things sane.

Merged from MOODLE_16_STABLE

Author: Donal McMullan <donal@catalyst.net.nz>

mod/chat/gui_header_js/chatinput.php

@@ -29,13 +29,25 @@
     ?>
     <script type="text/javascript">
     <!--
+    var waitFlag = false;
     function empty_field_and_submit() {
-        document.sendForm.chat_message.value = document.inputForm.chat_message.value;
-        document.inputForm.chat_message.value = '';
+        if(waitFlag) return false;
+        waitFlag = true;
+        var input_chat_message = document.getElementById('input_chat_message');
+        document.sendForm.chat_message.value = input_chat_message.value;
+        input_chat_message.value = '';
+        input_chat_message.className = 'wait';
         document.sendForm.submit();
-        document.inputForm.chat_message.focus();
         return false;
     }
+
+    function enableForm() {
+        var input_chat_message = document.getElementById('input_chat_message');
+        waitFlag = false;
+        input_chat_message.className = '';
+        input_chat_message.focus();
+    }
+
     // -->
     </script>
     <?php
@@ -46,7 +58,7 @@ function empty_field_and_submit() {
 ?>
     <form action="../empty.php" method="POST" target="empty" name="inputForm"
           OnSubmit="return empty_field_and_submit()">
-        &gt;&gt;<input type="text" name="chat_message" size="60" value="" />
+        &gt;&gt;<input type="text" id="input_chat_message" name="chat_message" size="60" value="" />
         <?php helpbutton('chatting', get_string('helpchatting', 'chat'), 'chat', true, false); ?>
     </form>
 

mod/chat/gui_header_js/insert.php

@@ -58,7 +58,7 @@
 
     if ($chatuser->version == 'header_js') {
         /// force msg referesh ASAP
-        echo '<script type="text/javascript">parent.jsupdate.location.href = parent.jsupdate.document.anchors[0].href;</script>';
+        echo '<script type="text/javascript">parent.jsupdate.location.href = parent.jsupdate.document.anchors[0].href;parent.input.enableForm();</script>';
     }
 
     redirect('../empty.php');

theme/standard/styles_color.css

@@ -709,6 +709,10 @@ table.message_search_results td {
   color:#888
 }
 
+#mod-chat-gui_header_js-chatinput .wait {
+    background: #dddddd;
+}
+
 /***
  *** Modules: Choice
  ***/