moveBefore() #273

Activity

1. github-actions

   added

   feature

   on Jul 15, 2025
2. github-actions

   added

   DOM

   on Sep 3, 2026
3. KavyanshKhaitan2 commented on Sep 19, 2026

   

   KavyanshKhaitan2

   on Sep 19, 2026

   Last edited by KavyanshKhaitan2

   More actions

   What I want to do with this feature

   I am currently using this at https://github.com/hackclub/twisted to preserve iFrame loading states when you try moving a window. This makes it so the iFrame doesnt reload every time one of the smaller windows are moved.

   What I'm having to do in the meantime

   I am currently using a polyfill that re-renders everything every time moveBefore is supposed to be called.

   <script>
       // MoveBefore polyfill for Safari (suggested by @Luke / U0BFDHWUSPM)
       (function () {
           // 1. Check if the native method is already supported
           if (typeof Element.prototype.moveBefore === 'function') return;
   
           // 2. Define the fallback function matching the moveBefore signature
           const moveBeforeFallback = function (nodeToMove, referenceNode) {
               if (!nodeToMove) {
               throw new TypeError("Failed to execute 'moveBefore': 1 argument required, but only 0 present.");
               }
               // Element.insertBefore(node, null) behaves exactly like appendChild
               return this.insertBefore(nodeToMove, referenceNode);
           };
   
           // 3. Apply the fallback across all valid ParentNode prototypes
           if (typeof Element !== 'undefined') {
               Element.prototype.moveBefore = moveBeforeFallback;
           }
           if (typeof Document !== 'undefined') {
               Document.prototype.moveBefore = moveBeforeFallback;
           }
           if (typeof DocumentFragment !== 'undefined') {
               DocumentFragment.prototype.moveBefore = moveBeforeFallback;
           }
       })();
   </script>