Note: if you have an AOSP ROM, this doesn't work because they use the AOSP webview by default which doesn't load web screens. You can get AOSP to use the Google WebView by going to developer options and there's a specific option for it. Switch to Google WebView and it should work as expected.
Easily use one of the pre-created Web Screens.
Start by using the Import Preset option to import any Web Screen preset you like.
Presets can be both created by the app's developer or by the app's users
If you want you can create a new preset by filling in the Web Screen Input Fields and then selecting Screen Preset Actions->Save
You can also show any web page as a screen by filling in the Source field manually and setting any other inputs you like.
If you make a link in the webpage have a source like
autotoolscommand://COMMAND_HERE
then when clicking that link, the COMMAND_HERE
AutoApps Command will be sent. React to it with the AutoApps event condition in Tasker.
If you want to send an AutoApps Command from javascript use the following code:
window.location.href = "autotoolscommand://COMMAND_HERE"
and the command will be sent.
You can use local files as images in the web page. Use the file's full paths to do that.