注意，下面的代码都不要在webview init中写，不会生效，需要在view did load之后才生效

直接上代码

设置JS Handler

// 防止循环应用
class LeakAvoider: NSObject {
    weak var delegate: WKScriptMessageHandler?

    init(delegate: WKScriptMessageHandler) {
        super.init()
        self.delegate = delegate
    }
}

extension LeakAvoider: WKScriptMessageHandler {
    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        delegate?.userContentController(userContentController, didReceive: message)
    }
}

// 我这里继承的WKWebview, delegate的实现也可以放view controller
extension SparkPageWebView: WKScriptMessageHandler{
    public func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        // message.body.type
    }
}

// 最后为webview设置代理, 注意要在view did load之后设置才会生效
self.configuration.userContentController.add(LeakAvoider(delegate: self), name: "xxx")

设置user agent

customUserAgent = Custom_User_Agent