Web development

Input/TV embedding

Web apps can embed connected external input sources in their DOM:

<video autoplay style="width:50%;height:50%">
  <source type="service/webos-external" src="ext://hdmi:1"></source>
</video>

Supported sources: ext://hdmi:1, ext://hdmi:2, ext://hdmi:3, ext://hdmi:4, ext://comp:1, ext://av:1, ext://av:2. Additionally, a TV stream can be embedded with src="tv://" and type="service/webos-broadcast"

It seems like only a single external input can be displayed at the same time (though this may be hardware-dependent).

This also partially works in the system browser (content is cut off whenever the status bar is visible), but one probably should not rely on this.

Userscripts in apps

JavaScript present in webOSUserScripts/userScript.js will be loaded as a userscript in app webviews / frames, including frames in origins outside of app root.

Example application that uses this: webosbrew/youtube-webos

Inspecting a running app, including ones you did not build, is covered in Inspecting a Web App.