How to determine with JavaScript, if the user is in internal or external Network?

Question

I have a button with a JavaScript that 'calls' a php-file. The site is accessible from the internal network and from the world wide web.

If I click the button from www the php is not working because the address in the JavaScript is an internal 192.168.x.x adress.

function doSomething(id)
{
            var url ="http://192.168.1.1/phpfile.php?id" +id;

            var win = window.open(url, '_blank');
                if(win){
                    //Browser has allowed it to be opened
                    win.focus();
                }
                else
                {
                    //Broswer has blocked it
                    alert('Please allow popups for this site');
                }
}

Is it possible to differentiate if the call is from the internal or another network?

In another case (php) I use an if-else to solve the problem

((substr($_SERVER['REMOTE_ADDR'],0,8) == "192.168.") ||($_SERVER['REMOTE_ADDR'] == "127.0.0.1")) 
? 'http://internal/address/' : 'http://my.external.de/''

@RayonDabre: Not entirely true. You can either hit an external service or use WebRTC as described in http://stackoverflow.com/questions/391979/get-client-ip-using-just-javascript. — str, Apr 06 '16 at 11:53

score 0 · Answer 1 · answered Apr 06 '16 at 12:04

If the button and the JavaScript-code reside in a HTML page delivered from the same server, it can test and set the correct value, before delivering this page.

$PREFIX = ((substr($_SERVER['REMOTE_ADDR'],0,8) == "192.168.") ||($_SERVER['REMOTE_ADDR'] == "127.0.0.1")) ? 'http://internal/address/' : 'http://my.external.de/''

function doSomething(id) { var url ="<?=PREFIX?>phpfile.php?id" +id; ....

score 0 · Accepted Answer · edited May 23 '17 at 11:45

As far I understand, you want your web site to work locally with localhost/192.168.x.x/127.0.0.1 or on the remote web server and distinguish which configuration you have so your javascript switch properly from one to the other.

First, you cannot get your IP address from javascript directly, you need to use a relay web site for this: see this thread for the answer.

But, in your case I believe there is a much more simpler way to proceed, and without any 'if'. Javascript (or the browser) is smart enough to route calls for you. Change your code to this:

function doSomething(id)
{
        var url ="/phpfile.php?id" +id;

        var win = window.open(url, '_blank');
            if(win){
                //Browser has allowed it to be opened
                win.focus();
            }
            else
            {
                //Broswer has blocked it
                alert('Please allow popups for this site');
            }
}

Your client browser will route the call to localhost automatically, if you loaded the page running the script, from localhost. And route to my.external.de, if you loaded the page running the script, from my.external.de.

I had to add a new virtual folder in the IIS, but it is working. Thank you! — dipa2016, Apr 06 '16 at 13:38

How to determine with JavaScript, if the user is in internal or external Network?

2 Answers2