Chrome Extension Content Script on https://chrome.google.com/webstore/

Question

Is Chrome blocking access to the webstore url?

I would like to make an extension that displays a like button beside the +1 button, but it looks like that content scripts are not working on https://chrome.google.com/webstore/*

Is that true?

Answer 1

TL;DR The webstore cannot be scripted by extensions, and the flag that previously allowed you to do that (--allow-scripting-gallery) has been removed in Chrome 35.

Chrome extensions cannot execute Content scripts / insert CSS the Chrome Web Store. This is explicitly defined in the source code, at function IsScriptableURL (click on the previous link to see the full logic).

  // The gallery is special-cased as a restricted URL for scripting to prevent   // access to special JS bindings we expose to the gallery (and avoid things   // like extensions removing the "report abuse" link).   // TODO(erikkay): This seems like the wrong test.  Shouldn't we we testing   // against the store app extent?   GURL store_url(extension_urls::GetWebstoreLaunchURL());   if (url.host() == store_url.host()) {     if (error)       *error = manifest_errors::kCannotScriptGallery;     return false;   } 

manifest_errors::kCannotScriptGallery is defined here:

const char kCannotScriptGallery[] =     "The extensions gallery cannot be scripted."; 

The error can be viewed in the background page's console when you use chrome.tabs.executeScript to inject a script in a Web Store tab. For instance, open https://chrome.google.com/webstore/, then execute the following script in the background page of an extension (via the console, for live debugging):

chrome.tabs.query({url:'https://chrome.google.com/webstore/*'}, function(result) {     if (result.length) chrome.tabs.executeScript(result[0].id, {code:'alert(0)'}); });