Detecting if a webpage is displayed as QWebEngineView

I am trying to use a qwebengineview to be able to display a certain webpage on my application. I add some javascript codes on web source. But I don't want the code to run when the webpage is displayed on a browser as it is designated only for app using qwebengineview. How do I fix this?

JavaScript has a standard object called navigator that contains data about the browser being used.