Fix #38: Add a loading message with progress on end-user interface

website/index.php

@@ -17,6 +17,8 @@ Access raw data with: <?php echoUrl('channels/'); ?>.
     <input type="submit" id="search-only-captions" value="Search only captions">
 </form>
 
+Progress: <span id="progress"></span>
+
 <ul id="channels">
 </ul>
 
@@ -36,8 +38,8 @@ Access raw data with: <?php echoUrl('channels/'); ?>.
 
     function treatLine(line) {
         console.log(line);
-        if (line.startsWith('alert:')) {
-            alert(line.replace('alert:', ''));
+        if (line.startsWith('progress:')) {
+            document.getElementById('progress').innerHTML = line.replace('progress:', '');
         } else {
             var channelsDom = document.getElementById('channels');
             const channelFileParts = line.split('/');