webview 去掉滚动条和上下黑灰色背景

// 去掉webView的滚动条
    for (UIView *subView in [webView subviews])
    {
        if ([subView isKindOfClass:[UIScrollView class]])
        {
            // 不显示竖直的滚动条
            [(UIScrollView *)subView setShowsVerticalScrollIndicator:NO];
        }
        //取消webview上下黑灰色背景
        webView.backgroundColor = [UIColor clearColor];
        [webView setOpaque:NO];
    }