直接代码 vv_wkView是懒加载 

// MARK: - web

extension FF_CookingWebVC: WKNavigationDelegate{

    funcwebView(_webView:WKWebView, didFinish navigation:WKNavigation!) {

        webView.evaluateJavaScript("document.body.offsetHeight") { (obj, error)in

            guardletheight = objas?CGFloatelse{return}

            self.vv_wkView.scrollView.contentSize=CGSize(width:UIScreen.main.bounds.width, height: height)

        }

        webView.evaluateJavaScript("document.readyState", completionHandler: { (complete, error)in

            ifcompleteas?String=="complete"&&!webView.isLoading{

                webView.evaluateJavaScript("document.body.scrollHeight", completionHandler: { (height, error)in

                    letheight = webView.scrollView.contentSize.height

                    self.vv_wkView.scrollView.contentSize=CGSize(width:UIScreen.main.bounds.width, height: height)

                })

            }

            self.ff_hudLoadingEnd(ff_animated:true)

        })

    }

}

如果url种有汉字 处理方法

url = url.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!

            self.vv_wkView.load(URLRequest(url:URL(string: url)!))