【Swift】WKWebViewの使い方

import WebKitを記述
WKNavigationDelegateを継承する
viewDidLoadに以下を追加
インスタンス.navigationDelegate = self
インスタンス.load(URLRequest(url: URL(string: "https://xxx.xx)!))
webViewメソッドを定義
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) { mainWebView.evaluateJavaScript("document.getElementById('loginId').value = 'maintenance';") mainWebView.evaluateJavaScript("document.getElementById('submitButton').click();") }

import UIKit
import WebKit
class SecondViewController: UIViewController,WKNavigationDelegate {
    @IBOutlet weak var mainWebView: WKWebView!
    override func viewDidLoad() {
        super.viewDidLoad()
        mainWebView.navigationDelegate = self
        mainWebView.load(URLRequest(url: URL(string: "https://google.com/")!))
    }
    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        mainWebView.evaluateJavaScript("document.querySelector('[name=\"q\"]').value = 'hoge';")
        mainWebView.evaluateJavaScript("document.getElementById('tsf').submit();")
    }
}