webextensions-examples/beastify/README.md

beastify

This add-on injects JavaScript into web pages. The addons.mozilla.org domain disallows this operation, so this add-on will not work properly when it's run on pages in the addons.mozilla.org domain.

What it does

The extension includes:

• a browser action with a popup including HTML, CSS, and JS
• a content script
• three images, each of a different beast, packaged as web accessible resources

When the user clicks the browser action button, the popup is shown, enabling the user to choose one of three beasts.

When they choose a beast, the extension injects the content script into the current page, and sends the content script a message containing the name of the chosen beast.

When the content script receives this message, it replaces the current page content with an image of the chosen beast.

When the user clicks the reset button, the page reloads, and reverts to its original form.

What it shows

• write a browser action with a popup
• give the popup style and behavior using CSS and JS
• inject a content script programmatically using tabs.executeScript()
• send a message from the main extension to a content script
• use web accessible resources to enable web pages to load packaged content
• reload web pages