Question

I have page where RSS icon is present. I want that when user clicks on RSS icon it will check in chrome browser that, whether that RSS reader chrome extension is installed or not
I am trying to achieve this by using chrome extension methods, mentioned here.

I tried something like this but it is not working:

var port = chrome.extension.connect("nlbjncdgjeocebhnmkbbbdekmmmcbfjd");

Answer 1

To use this API you need to be either an extension or a web application having the necessary permissions – normal web pages cannot access it. However, detecting whether an extension is installed in Chrome is still easy:

<script src="chrome-extension://nlbjncdgjeocebhnmkbbbdekmmmcbfjd/manifest.json"
        onload="alert('installed')" onerror="alert('not installed')"></script>

This uses the fact that the extension’s manifest.json file is located under a predictable URL and that web pages are allowed to load this URL. Of course, this isn’t an officially documented approach but rather a loophole and a privacy issue. So be prepared for it to stop working in some future Chrome version. At the moment it works however.