Google Chrome extension installed popup

While installing the Google ex开发者_运维知识库tensions form chrome web store it shows some popup like "Google Chrome extension is now installed".

I want similarly, while login I need to show the login popup.

Please suggest me on this.

You can create either a browser action or a page action popup. You can change popup html dynamically to make it look completely different depending on the situation but you can't open it programmatically (desktop notifications could be used for alerts).