MagazineViewController.swift

import UIKit
import WebKit

class MagazineViewController: UIViewController, UIWebViewDelegate {
    
    @IBOutlet weak var webview: UIWebView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // TODO replace URL here
        let url = URL(string: "https://www.mrgoodlife.net/en/")
        webview.loadRequest(URLRequest(url: url!))
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
    
    func webViewDidStartLoad(_ webView: UIWebView) {
        if webview.canGoBack {
            self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "BACK", style: UIBarButtonItemStyle.plain, target: self, action: #selector(goBack))
        } else {
            self.navigationItem.leftBarButtonItem = nil
        }
        
    }
    
    @objc func goBack() {
        webview.goBack()
    }
    
}