title: public http server to test internet connection
body: <p>In a javascript client app, when a user can't connect to the app's servers, i would like to differenciate the 2 different cases:</p>
  <ol>
  <li>My servers are down</li>
  <li>The client's connection to the server is down</li>
  </ol>
  <p>I could find nothing usefull in javascript because it detects either if the user is connected to any network, or if the network card is plugged, or useless things of this sort. I found out the only way to be sure is to issue a form of request to another server on internet and compare the responses.</p>
  <p>So my question is: <strong>Does it exist a public server by ICANN or another public entity that allows to do such a request on their servers, to find out if the user is actually having a valid internet connection ?</strong></p>