Update index.html

index.html

@@ -1015,11 +1015,13 @@ document.addEventListener('DOMContentLoaded', function() {
         if (combinedAudioSource) {
             combinedAudioSource.playbackRate.value = speed;
             // ピッチを維持する設定
-            if ('preservesPitch' in combinedAudioSource) {
-                combinedAudioSource.preservesPitch = true;
-            } else if ('preservePitch' in combinedAudioSource) {
-                combinedAudioSource.preservePitch = true; // 古いブラウザ用
-            }
+                if ('preservesPitch' in combinedAudioSource) {
+                    combinedAudioSource.preservesPitch = value; // モダンブラウザ
+                } else if ('webkitPreservesPitch' in combinedAudioSource) {
+                    combinedAudioSource.webkitPreservesPitch = value; // 古い WebKit (Chrome <86 など)
+                } else if ('mozPreservesPitch' in combinedAudioSource) {
+                    combinedAudioSource.mozPreservesPitch = value; // 古い Gecko (Firefox ≤100)
+                }
         }
         
         speedValue.textContent = speed.toFixed(2) + 'x';