有三种实现途径

1. WKScriptMessageHandler

OC部分：注册并实现Handler
将OC中的方法"nativeMethod"注册为JavaScript Message Handler，从而WebView中的JavaScript代码可以调用该方法

// Register in Objective-C code
- (void)setupWKWebView
{// [WKWebViewConfiguration alloc]返回一个被分配和初始化的WKWebViewConfiguration对象的指针// init方法是WKWebViewConfiguration类的实例方法WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init];configuration.userContentController = [[WKUserContentController alloc] init];// 将OC中的方法"nativeMethod"注册为JavaScript Message Handler，从而可以在WebView中执行JavaScript代码时调用该方法[configuration.userContentController addScriptMessageHandler:self // addScriptMessageHandler是方法名，self是参数1name:@"nativeMethod"]; // name是参数2// 初始化WKWebViewWKWebView *webView = [[WKWebView alloc]initWithFrame:self.view.frameconfiguration:configuration];
}// Handler method defined in WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController //userContentController是参数1didReceiveScriptMessage:(WKScriptMessage *)message //message是参数2
{if ([message.name isEqualToString:@"nativeMethod"]) // 当JS端调用的是nativeMethod时{... //OC端的handler逻辑实现}
}

JS部分：调用Handler
调用"nativeMethod"

// Invoke in JavaScript code
window.webkit.messageHandlers.nativeMethod.postMessage();

2. WebViewJavascriptBridge

OC部分：注册并实现Handler
注册名为"nativeMethod"的Handler

// OC中 调用bridgeForWebView:方法，来初始化WebViewJavascriptBridge
// self.bridge将被设置为WKWebView的navigationDelegate属性
self.bridge = [WebViewJavascriptBridge bridgeForWebView:webView];[self.bridge registerHandler:@"nativeMethod" //参数1，JS端以这个函数名调用该注册的native方法handler: //参数2的参数名，冒号后面跟着参数2的参数值，是一个block；当JS端调用nativeMethod方法时，OC端执行该block^(id data, WVJBResponseCallback responseCallback) // ^代表后面是一个block // data是JS端传递过来的数据// responseCallback是 OC端的 block 执行完毕之后，往 JS 端传递的数据{... // block中的代码，这些代码在JS端调用nativeMethod时被执行}
];

JS部分：调用Handler

WebViewJavascriptBridge.callHandler('nativeMethod', data, function(responseData) {// 处理来自Objective-C的响应数据console.log(response); 
});

例如我们使用Frida分析出来，某app的wkwebview中有如下handler：

{callNavigationSelectView = "<__NSMallocBlock__: 0x281d4a440>";checkNotificationPermission = "<__NSMallocBlock__: 0x281d4b240>";clickControlToShare = "<__NSMallocBlock__: 0x281d4bf00>";couponPaySuccess = "<__NSMallocBlock__: 0x281d4a780>";doQRScan = "<__NSMallocBlock__: 0x281d4bf80>";faceDetect = "<__NSMallocBlock__: 0x281d4bcc0>";getDeviceAlipay = "<__NSMallocBlock__: 0x281d4a4c0>";getDeviceId = "<__NSMallocBlock__: 0x281d4a800>";getDeviceInfo = "<__NSMallocBlock__: 0x281d4a680>";getLocation = "<__NSMallocBlock__: 0x281d4a600>";getNetworkStatus = "<__NSMallocBlock__: 0x281d4b0c0>";getOtherDeviceInfo = "<__NSMallocBlock__: 0x281d4b540>";getSMDeviceId = "<__NSMallocBlock__: 0x281d4a2c0>";getTripEmail = "<__NSMallocBlock__: 0x281db04c0>";getUserInfo = "<__NSMallocBlock__: 0x281d4a540>";goToKF = "<__NSMallocBlock__: 0x281d4a340>";goToVideoPlayer = "<__NSMallocBlock__: 0x281d4a700>";hideLoadingDialog = "<__NSMallocBlock__: 0x281d4b3c0>";jdPayHandle = "<__NSMallocBlock__: 0x281d4b900>";jumpToMiniPro = "<__NSMallocBlock__: 0x281d4a380>";requestNotificationPermission = "<__NSMallocBlock__: 0x281d4af00>";saveImage = "<__NSMallocBlock__: 0x281d4a500>";sendMsg = "<__NSMallocBlock__: 0x281d4a5c0>";shareOnTheWebviewPage = "<__NSMallocBlock__: 0x281d4a640>";shareWxImages = "<__NSMallocBlock__: 0x281d4b4c0>";shareWxMinipg = "<__NSMallocBlock__: 0x281d4a580>";startAuthoritySetting = "<__NSMallocBlock__: 0x281d4a300>";startNetworkSetting = "<__NSMallocBlock__: 0x281d4a7c0>";statusBarShare = "<__NSMallocBlock__: 0x281d4ad40>";uploadTripEmail = "<__NSMallocBlock__: 0x281d49b40>";webviewClose = "<__NSMallocBlock__: 0x281d4a740>";webviewGoBack = "<__NSMallocBlock__: 0x281d4a480>";
}

这时候在JS端就可以这么调用：

WebViewJavascriptBridge.callHandler('getLocation', function(response) {console.log(response); 
});

确实能调用起来

3. DSBridge

这个不是很常见

OC部分：

@implementation JsObject
- (NSString *) nativeMethod:(NSString *) msg
{...
}
@endDWKWebView* dwebview = [[DWKWebView alloc] initWithFrame:bounds];
[dwebview addJavascriptObject:[[JsObject alloc] init] namespace:nil];

JS部分：

var dsBridge=require("dsbridge");
var str=dsBridge.call("nativeMethod","arg");

参考：
Medusa Attack: Exploring Security Hazards of {In-App}{QR} Code Scanning[C]//32nd USENIX Security Symposium (USENIX Security 23). 2023: 4607-4624.