使用Swift WKWebView 打开包含中文，特殊字符 # % * 等特殊字符的链接，会出现链接不能访问的情况（安卓端和pc可以正常访问）。
解决这个问题，需要将urlString进行一下处理。
var urlString: String?
let webView = WKWebView(frame: CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight - navigationHeight ), configuration: WKWebViewConfiguration())
let charSet = CharacterSet.urlQueryAllowed as NSCharacterSet
let mutSet = charSet.mutableCopy() as! NSMutableCharacterSet
mutSet.addCharacters(in: "#")
let encodingURL = urlString?.addingPercentEncoding(withAllowedCharacters: mutSet as CharacterSet)
let myURL = NSURL.init(string: encodingURL!)
if myURL == nil {
return
}
let myRequest = URLRequest(url: myURL! as URL)
webView.load(myRequest)
