Current URL. Useful for deep links and naming testing.

IP

Opening child windows

File selection. Check that your device allows you to attach multiple different files. Often used for document verification.

Social networks and messengers

The YouTube player allows you to check both audio playback and full-screen mode with a change of orientation in it

Playing Sounds with HTML5 Audio

Check other functions: camera, opening child windows and dialogs using JS (rarely used). Also, here you can navigate to you own address

Saving authorizations and other data using cookies

Window adaptation to variable screen space. Click on the input field and check that you are still able to fill the fields.