阻止冒泡 阻止默认事件

if ( event && event.stopPropagation ) {
   event.stopPropagation();
}else {
   window.event.cancelBubble = true; 
} 
   

     if ( event && event.preventDefault ) {
          event.preventDefault(); 
        }else{
          window.event.returnValue = false; 
        // return false; 
        }