func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {  let jsGetImages =    "function getImages(){" +    "var objs = document.getElementsByTagName(/"img/");" +    "var imgScr = '';" +    "for(var i=0;i<objs.length;i++){" +    "imgScr = imgScr + objs[i].src + '+';" +    "};" +    "return imgScr;" +    "};"  webView.evaluateJavaScript(jsGetImages, completionHandler: nil)  webView.evaluateJavaScript("getImages()") { (data, err) in    let imageUrl:String = data as! String    var urlArry = imageUrl.components(separatedBy: "+")    urlArry.removeLast()    self.imgUrlArray.addObjects(from: urlArry)    for url in self.imgUrlArray{      let photo = SKPhoto.photoWithImageURL(url as! String)      photo.shouldCachePhotoURLImage = false // you can use image cache by true(NSCache)      self.images.append(photo)    }  }  var jsClickImage:String  jsClickImage =     "function registerImageClickAction(){" +    "var imgs=document.getElementsByTagName('img');" +    "var length=imgs.length;" +    "for(var i=0;i<length;i++){" +    "img=imgs[i];" +    "img.onclick=function(){" +    "window.location.href='image-preview:'+this.src}" +    "}" +    "}"  webView.evaluateJavaScript(jsClickImage, completionHandler: nil)  webView.evaluateJavaScript("registerImageClickAction()", completionHandler: nil)}

func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {  let requestString = navigationAction.request.url?.absoluteString  print(requestString!)  if (requestString?.hasPrefix("image-preview"))!{    let imgUrl = NSString.init(string: requestString!).substring(from: "image-preview:".count )    let index = imgUrlArray.index(of: imgUrl)    let browser = SKPhotoBrowser(photos: images)    browser.initializePageIndex(index)    present(browser, animated: true, completion: {})  }  decisionHandler(.allow) //一定要加上這句話 }