I am going to test my website speed, primary the webserver latency. Summarize what I want to achieve:

1) a webpage with javascript hosted in my website(http://myweb.com/test-speed.html)

2) I give this url to my friends

3) They don't need to do anything, they just need to access this webpage then the latency is printed out in the webpage.

4) If the webpage can also tell which state the visitor is in(using IP address range database), it will be a plus.

Any existing solutions? I can modify the javascript to log the data into database, but I think the core here is how to writ the javascript to know the latency.