This is simple webpage that checks whether your internet is working or not every 5 seconds. If in case your internet goes down, it notifies you with a sound message.
Use this tool when you have to download a very large file but you are on an unstable internet connection. You might want to be notified immediately once the internet is down so you can check where's the problem, fix and resume the download immediately. This basically saves you the frustration of coming back to your computer after few hours or so, only to realize your internet went down during the download.
You can also screenshot the logs from this tool to show your ISP that your internet is not working properly.
This page is open-source. Contributions are welcomed!