我有以下代码
<center><input type="button" value="Pause" onClick="jwplayer('video1').pause(true);jwplayer('video2').pause(true);;jwplayer('video3').pause(true);;jwplayer('video4').pause(true);;"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
<input type="button" value="Play" onClick="jwplayer(video1).pause(false);jwplayer(video2).pause(false);;jwplayer(video3).pause(false);;jwplayer(video4).pause(false);;"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
<input type="button" value="Mute" onClick="jwplayer(video1).setVolume(0);jwplayer(video2).setVolume(0);;jwplayer(video3).setVolume(0);;jwplayer(video4).setVolume(0);;"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
<input type="button" value="Mute 1,2" onClick="jwplayer(video1).setVolume(0);"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
<input type="button" value="Mute 3,4" onClick="jwplayer(video3).setVolume(0);"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
<input type="button" value="Unmute" onClick="jwplayer(video1).setVolume(100);;jwplayer(video3).setVolume(100);"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
<input type="button" value="<-30" onClick="jwplayer(video1).getPosition(); position -= 30; jwplayer().seek(position);jwplayer(video2).getPosition(); position -= 30; jwplayer().seek(position);;jwplayer(video3).getPosition(); position -= 30; jwplayer().seek(position);;jwplayer(video4).getPosition(); position -= 30; jwplayer().seek(position);;"style="background:rgba(192,192,192,0.3);color:white;font-weight:bold" name="button2">
</center></div>
除<-30以外的所有功能都可以正常倒转所有4个玩家30秒，你知道我在做什么错吗？任何建议或帮助都会很棒！