let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
    let userScript = WKUserScript(source: jscript, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
    let wkUController = WKUserContentController()
    wkUController.addUserScript(userScript)
    let wkWebConfig = WKWebViewConfiguration()
    wkWebConfig.userContentController = wkUController
    let yourWebView = WKWebView(frame: self.view.bounds, configuration: wkWebConfig)// yourwebview is the webview that you are using.