index.html

<!DOCTYPE html>
<html>
<head>
	<title>YTPC (You watch Tube on PC)</title>
<style type="text/css">
* { padding: 0; margin: 0; }
html, body, #foo {
    height: 100%;
}

#foo {
    width: 100%;
}

#download {
    position: absolute;
    bottom: 0px;
    width: 100%;
}
</style>
</head>
<body>
<webview id="foo" src="https://www.youtube.com/"></webview>

<script>

  const { remote } = require('electron')
  const { Menu, MenuItem } = remote
  const customTitlebar = require('custom-electron-titlebar');

  let MyTitleBar = new customTitlebar.Titlebar({
    backgroundColor: customTitlebar.Color.fromHex('#444'),
    shadow: true
  });

  const isMac = process.platform === 'darwin'

  const menu = new Menu();

  menu.append(new MenuItem({
    label: 'เมนูหลัก',
    submenu: [
      isMac ? { label: 'ปิด',role: 'close' } : { label: 'ออกจากโปรแกรม',role: 'quit' }
    ]
  }));

  MyTitleBar.updateMenu(menu);

  MyTitleBar.updateTitle('YTPC');

  onload = () => {
    const webview = document.querySelector('webview')
    const indicator = document.querySelector('.indicator')

    const loadstart = (e) => {
      
      updatedownload()

    }

     const loadstop = (e) => {
      
      updatedownload()

    } 

    webview.addEventListener('did-start-loading', loadstart)
    webview.addEventListener('did-stop-loading', loadstop)
  }
  
  function updatedownload() {
    if (foo.getURL().search("watch") >= 0) {
      
    const menu = new Menu();

      menu.append(new MenuItem({
        label: 'เมนูหลัก',
        submenu: [
          {
            label: 'ดาว์นโหลด วิดีโอนี้',
            click: async () => {
              const { shell } = require('electron')
              await shell.openExternal('https://th.savefrom.net/#url=' + foo.getURL())
            }
          },
          isMac ? { label: 'ปิด',role: 'close' } : { label: 'ออกจากโปรแกรม',role: 'quit' }
        ]
      }));

      MyTitleBar.updateMenu(menu);

    } else {

      const menu = new Menu();

      menu.append(new MenuItem({
        label: 'เมนูหลัก',
        click: async () => {
          window.close();
        }
      }));

      MyTitleBar.updateMenu(menu);

    }
  }

</script>

</body>
</html>