iOS WKWebView Swift javascript enable

For those who are building for iOS 14 with Swift 5 and Xcode 12, it has changed to the following ...

webView.configuration.defaultWebpagePreferences.allowsContentJavaScript = true

Working with WKWebView is better to create it from code. And you can set javaScriptEnabled to configuration:

let preferences = WKPreferences()
preferences.javaScriptEnabled = true
let configuration = WKWebViewConfiguration()
configuration.preferences = preferences
let webview = WKWebView(frame: .zero, configuration: configuration)

Update. This is WKWebView in view controller class:

import UIKit
import WebKit

class ViewController: UIViewController {

    private var webView: WKWebView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let preferences = WKPreferences()
        preferences.javaScriptEnabled = true
        let configuration = WKWebViewConfiguration()
        configuration.preferences = preferences
        webView = WKWebView(frame: view.bounds, configuration: configuration)
        view.addSubview(webView)
    }
}

You are using WKWebView storyboard view so you can directly access the configuration. So use preferences under your WKWebView configuration.

import WebKit

class ViewController: UIViewController {

  @IBOutlet weak var webView: WKWebView!

  override func viewDidLoad() {
    super.viewDidLoad()
    let url = URL(string: "http://132.148.136.31:8082")
    let urlRequest = URLRequest(url: url!)

    // enable JS
    webView.configuration.preferences.javaScriptEnabled = true
    webView.load(urlRequest)
  }
}

The above answer is right you need to set this value as true to enable JavaScript.

webView.configuration.preferences.javaScriptEnabled = true

But if the JS scripts are from a non-HTTPS source then you need to allow "App Transport Security's Arbitrary Loads".

Here is how to fix that:

1. Navigate to Project Settings/Target/[your app's target]/Info.
2. Check whether there is a dictionary called App Transport Security Settings. If not, create it.
3. Inside it, create a boolean value called Allow Arbitrary Loads (if it's not there yet) and set it to YES.

If you check the official documentation of javaScriptEnabled or allowsContentJavaScript, it says:

The default value of this property is true.

So, you don't even need to write this if you don't disable it somewhere else.

However, if you need to enable javascript for WKWebView, here is how to do it:

iOS 14 and above:

webView.configuration.defaultWebpagePreferences.allowsContentJavaScript = true

iOS 13 and below:

webView.configuration.preferences.javaScriptEnabled = true

IOS 15.5

add this

webView.configuration.defaultWebpagePreferences.allowsContentJavaScript = true

try this code :

 override func viewDidLoad() {
    super.viewDidLoad()
    configureWebView()
    currentWebView.load(requestURL)
}

private func configureWebView() {
    webView.navigationDelegate = self
    webView.uiDelegate = self
    webView.allowsBackForwardNavigationGestures = true
    /// javaScript 사용 여부
    if #available(iOS 14, *) {
        let preferences = WKWebpagePreferences()
        preferences.allowsContentJavaScript = true
        webView.configuration.defaultWebpagePreferences = preferences
    }
    else {
        webView.configuration.preferences.javaScriptEnabled = true
        /// user interaction없이 윈도우 창을 열 수 있는지 여부를 나타냄. iOS에서는 기본값이 false이다.
        webView.configuration.preferences.javaScriptCanOpenWindowsAutomatically = true
    }
}

func createNewWebView(_ config: WKWebViewConfiguration) -> WKWebView {
    /// autoLayout 되어 있는 webView와 frame을 같게 한다.
    let newWebView = WKWebView(frame: webView.frame,
                               configuration: config)
    newWebView.navigationDelegate = self
    newWebView.uiDelegate = self
    newWebView.allowsBackForwardNavigationGestures = true
    view.addSubview(newWebView)
    popupWebViews.append(newWebView)
    return newWebView
}