Cleanup and make code compliant with ts

static/sfu.js

@@ -1194,7 +1194,6 @@ function updateControlStatus(id, isLocal, shared, audioMode, muted) {
  * @param {string} peerid
  */
 function registerControlEvent(peerid) {
-    let settings = getSettings();
     let peer = document.getElementById(peerid);
     //Add event listener when a video component is added to the DOM
     let volume = /** @type {HTMLElement} */(peer.querySelector("span.volume"));
@@ -1245,24 +1244,30 @@ function registerControlEvent(peerid) {
         };
     }
 
-    let media = /** @type {HTMLElement} */(peer.querySelector("video.media"));
+    let media = /** @type {HTMLVideoElement} */(peer.querySelector("video.media"));
+    /** @ts-ignore */
+    if(media.onenterpictureinpicture && media.onleavepictureinpicture) {
+        /** @ts-ignore */
         media.onenterpictureinpicture = function(event) {
             if(event.target.classList.contains('media-static'))
                 return;
             event.target.classList.remove('media-mirror');
         };
 
+        /** @ts-ignore */
         media.onleavepictureinpicture = function(event) {
             if(event.target.classList.contains('media-static'))
                 return;
             event.target.classList.add('media-mirror');
         };
+    }
 
     let stop = /** @type {HTMLElement} */(peer.querySelector(".stopsharing"));
     if (stop) {
         stop.onclick = function(event) {
             event.preventDefault();
-            let video = getParentVideo(event.target);
+            let element = /** @type {HTMLElement} */(event.target);
+            let video = getParentVideo(element);
             let video_id = video.id.split("-")[1];
             for(let id in serverConnection.up) {
                 if (video_id === id) {