jQuery(document).ready(function() { 
    $('#musiclist').find('.li_all').show();
    $('#musiclist').find('.li_all').hover(
     function() {$(this).find('.detail_dis').slideDown();
     if(isFirefox=navigator.userAgent.indexOf("Firefox")>0){
          $('.detail_dis').css('display','block');
       }
     },
     function() {$(this).find('.detail_dis').slideUp();
     if(isFirefox=navigator.userAgent.indexOf("Firefox")>0){
          $('.detail_dis').css('display','none');
       }

     }
    );
});