for (UIView *viewin [_webViewsubviews]){
if ([viewisKindOfClass:[UIScrollView class]]){
for (UIView *shadowViewin view.subviews){
// 上下滚动出边界时的黑色的图片 也就是拖拽后的上下阴影
if ([shadowViewisKindOfClass:[UIImageView class]]){
shadowView.hidden =YES;
}
}
}
}