Upload algebra.html

algebra.html

@@ -512,12 +512,19 @@
         }
 
         function getPointer(e) {
+            // For touchend event, we need to use changedTouches because touches is empty.
+            if (e.changedTouches && e.changedTouches.length > 0) {
+                return { x: e.changedTouches[0].clientX, y: e.changedTouches[0].clientY };
+            }
+            // For touchstart and touchmove events.
             if (e.touches && e.touches.length > 0) {
                 return { x: e.touches[0].clientX, y: e.touches[0].clientY };
             }
+            // Fallback for mouse events.
             return { x: e.clientX, y: e.clientY };
         }
 
+
         function moveClone(x, y) {
             if (!clone) return;
             clone.style.left = `${x - offset.x}px`;
@@ -568,4 +575,4 @@
     </script>
 
 </body>
-</html>
+</html>