导航栏返回监听 - 自定义导航栏按钮图片 - WKWebView

1. 导航栏返回监听 - 自定义导航栏按钮图片 -- Swift

let leftBarBtn = UIBarButtonItem(title: "", style: .plain, target: self,action: #selector(backToPrevious))
        leftBarBtn.image = UIImage(named: "arrow--return")
        self.navigationItem.leftBarButtonItem = leftBarBtn;

//返回按钮
    func backToPrevious(){
        self.navigationController?.popViewController(animated: true);
    }

2. iOS WKWebView的使用