怎樣去掉UIWebView 右側的滾動條，和滾動時出界後的黑色背景

如題，隱藏滾動條和上下滾動時出邊界的後面的黑色的背景

aWebView.backgroundColor=[UIColor clearColor];
   for (UIView *_aView in [aWebView subviews])
   {
    if ([_aView isKindOfClass:[UIScrollView class]])
       {
           [(UIScrollView *)_aView setShowsVerticalScrollIndicator:NO]; //右側的滾動條

        for (UIView *_inScrollview in _aView.subviews)
           {

               if ([_inScrollview isKindOfClass:[UIImageView class]])
               {
                   _inScrollview.hidden = YES;  //上下滾動出邊界時的黑色的圖片
               }
        }
    }
}