Is there anyway with javascript/jQuery to check if a website is up?
You're limited by the single origin policy I don't think you can use a standard Ajax request, but is it possible to try and load a file (similar to wget) and get the status code of the reply another way?
This would be for a user side website checker, where they can check if multiple domains are "up" without having to use any code on a server.
e.g. I open a web page at checkmysite.org
it sends an HTTP request to mysite.org
to check whether it receives a response, and if so the domain is online