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33d8fba6a8
* Added an example for contentScripts.register * Use messaging instead of getBackgroundPage
25 lines
1.9 KiB
Markdown
25 lines
1.9 KiB
Markdown
# User script
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This extension demonstrates the `browser.contentScripts.register()` API, which enables an extension to register URL-matching content scripts at runtime.
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This extension adds a browser action that shows a popup. The popup lets you specify:
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* some code that comprises your content script
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* one or more [match patterns](https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Match_patterns), comma-separated. The content script will only be loaded into pages whose URLs match these patterns.
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Once these are set up you can register the content script by clicking "Register script". The extension will then register a content script with the given properties by calling `browser.contentScripts.register()`.
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To keep things simple, you can only have one script registered at any time: if you click "Register script" again, the old script is unregistered. To do this, the extension keeps a reference to the `RegisteredContentScript` object returned from `browser.contentScripts.register()`: this object provides the `unregister()` method.
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Note that the extension uses a background script to register the content scripts and to keep a reference to the `RegisteredContentScript` object. If it did not do this, then as soon as the popup window closed, the `RegisteredContentScript` would go out of scope and be destroyed, and the browser would then unregister the content script as part of cleanup.
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## Default settings
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The popup is initialized with some default values for the pattern and the code:
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* the pattern `*://*.org/*`, which will load the script into any HTTP or HTTPS pages on a `.org` domain.
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* the code `document.body.innerHTML = '<h1>This page has been eaten<h1>'`
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To try the extension out quickly, just click "Register script" with these defaults, and load http://example.org/ or
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https://www.mozilla.org/. Then try changing the pattern or the code, and reloading these or related pages.
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