title: Is it possible for the webpage to detect that it is accessed from the webview app?
body: <p>Let's say I have a website that contains only 2 pages.</p>
  
  <ol>
  <li><a href="http://example.com" rel="nofollow noreferrer">http://example.com</a></li>
  <li><a href="http://example.com/webview.html" rel="nofollow noreferrer">http://example.com/webview.html</a></li>
  </ol>
  
  <p>Then I created a webview react native application it can be simple as this:</p>
  
  <p><strong>App.js</strong></p>
  
  <pre><code>import React, { Component } from 'react';
  import { WebView } from 'react-native';
  
  export default class MyWeb extends Component {
    render() {
      return (
        &lt;WebView
          source={{uri: 'http://example.com/webview.html'}}
          style={{marginTop: 20}}
        /&gt;
      );
    }
  }
  </code></pre>
  
  <p>Now my question is: Is it possible for the webpage to detect that it is accessed from the webview app?</p>
  
  <p>Let's say I have a condition in the webview.html file like:</p>
  
  <pre><code>if ( webview ) {
    return 'webview';
  }
  else {
    return 'normal browser'
  }
  </code></pre>
  
  <p>Maybe something like inserting a javascript, maybe a variable from the webview to webpage? Then I can use that variable to check its existence then if it exists then it is webview, else it is not.</p>
  
  <p>I know javascript can detect the browser used, screen resolution, os, and etc. So is this possible?</p>
  
  <p>The app has a target OS of Android and iOS.</p>