JS: Update external links exactly once per second

assets/js/player.js

@@ -114,12 +114,23 @@ function addCurrentTimeToURL(url, base) {
     return urlUsed;
 }
 
+/**
+ * Global variable to save the last timestamp (in full seconds) at which the external
+ * links were updated by the 'timeupdate' callback below.
+ *
+ * It is initialized to 5s so that the video will always restart from the beginning
+ * if the user hasn't really started watching before switching to the other website.
+ */
+var timeupdate_last_ts = 5;
+
 /**
  * Callback that updates the timestamp on all external links
  */
 player.on('timeupdate', function () {
-    // Only update once every 5 seconds
-    if ((Math.ceil(player.currentTime()) % 5) != 0) return;
+    // Only update once every second
+    let current_ts = Math.floor(player.currentTime());
+    if (current_ts > timeupdate_last_ts) timeupdate_last_ts = current_ts;
+    else return;
 
     // YouTube links