             self.isLoading = true
             //上一条新闻
             getPreviousNews()
-        }else if (-offSetY > 40) {//到－80 让webview不再能被拉动
-            self.webView.scrollView.contentOffset = CGPointMake(0, -40);
-        }
-        
-        if (offSetY + ScreenHeight > scrollView.contentSize.height + 20  && !self.webView.scrollView.dragging) {
+        }else if (-offSetY > 60) {//到－80 让webview不再能被拉动
+            self.webView.scrollView.contentOffset = CGPointMake(0, -60);
+        }
+        
+        if (offSetY + ScreenHeight + 80 > scrollView.contentSize.height  && !self.webView.scrollView.dragging) {
             if !viewModel.hasNext {
                 return
             }

        backgroundImg = UIImageView()
        backgroundImg.contentMode = .ScaleAspectFill
        backgroundImg.clipsToBounds = true
        backgroundImg.frame = CGRectMake(0, -40, ScreenWidth, CGFloat(IN_WINDOW_HEIGHT+40))
        
        titleLabel = UILabel()
        titleLabel.numberOfLines = 0

            BlackStatusBar()
        }
        
        if (-offSetY <= 60 && -offSetY >= 50) {
            if !viewModel.hasPrevious {
                return
            }
