Sounds Music not synchronised

Hello everyone.

We have been developed some small games with cocos2d html5. The only problem we have is with sound effects and music. When we upload these games on the web the sound effects and music are playing but with a delay. In Firefox and Chrome delay isn’t very big but in Safari is bigger.
The sounds and music are being preloaded on the applicationDidFinishLaunching:function. LocalHost are ok. Did anyone face the same problem?

Thanks, Stelios