使用postMessage处理程序将数据从WKWebview's网页发送到本地代码，

import UIKit
import WebKit

class ViewController: UIViewController, WKScriptMessageHandler {

    lazy var webView: WKWebView = {
        let   webCfg:WKWebViewConfiguration = WKWebViewConfiguration()

        // Setup WKUserContentController instance for injecting user script
        var userController:WKUserContentController = WKUserContentController()

        // Add a script message handler for receiving  "buttonClicked" event notifications posted from the JS document using  window.webkit.messageHandlers.postMessageListener.postMessage(JSON.stringify({data})) script message
        userController.add(self, name: "nativeListener")
        // Configure the WKWebViewConfiguration instance with the WKUserContentController
        webCfg.userContentController = userController;

        let webView = WKWebView(frame: CGRect(x: 0, y: 0, width: self.view.frame.width, height: self.view.frame.height), configuration: webCfg)
        return webView
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        webView.configuration.preferences.javaScriptEnabled = true
        self.view.addSubview(webView)
        let urlToLoad  = URL(string: "your_url_string")
        // Do any additional setup after loading the view.
        webView.load(URLRequest(url:urlToLoad!))
    }

    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
     if message.name == "nativeListener" {
          print(message.body) // prints the data that is sent from javascript
       }
    }
}

有关简单的解释，您可以查看这篇文章：
https://medium.com/@hoishing/using-javascript-with-wkwebview-64f94153ad0
如果你想要更深入的解释，你可以检查这另一篇文章：
https://dev.to/gualtierofr/wkwebview-and-javascript-interaction-1pbl
在这两篇文章中，他们都提到了如何从Swift触发Javascript函数以及如何接收Javascript消息
无论如何，如果你在JavaScript中执行这个函数：

window.webkit.messageHandlers.postMessageListener.postMessage(JSON.stringify({data}))

您必须通过以下方式在Swift中监听名称postMessageListener：
设置WKWebView

let preferences = WKPreferences()
preferences.javaScriptEnabled = true
let configuration = WKWebViewConfiguration()
configuration.preferences = preferences

// Here I am guessing that the Frame of the WebView is the entire Screen
let webView = WKWebView(frame: view.frame, configuration: configuration)

configuration.userContentController.add(self, name: "postMessageListener")

符合方案WKScriptMessageHandler

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
   if message.name == "postMessageListener" {
       // Manage your Data
   }
}