Need Javascript to change an ad tracker key based off sub domain name

Question

I've currently got 4 different javascripts for ad tracking. They look something like this:

<script type='text/javascript'> var TrackerKey = 'keyabc123'; var url = 'http://website.com/jscode.js'; var script = document.createElement('script'); script.setAttribute('src', url); script.setAttribute('type', 'text/javascript'); document.body.appendChild(script);</script>

I want to combine all 4 and simply have the tracker key swap out based off the sub domain name they're on.

Thus far I've been able to work out that I would use the window.location.hostname to find what the domain is. And I would probably use a switch statement or if/else approach.

I'm not experienced enough though to know how to pass on the information of what the domain is as a variable to the switch statement, and then use that to update the tracker key variable.

I assume it might look something like the following...

<script type='text/javascript'> 

var domain = window.location.hostname;

var TrackerKey;
switch (???) {
    case 0:
        sub.domain1.com = "keyabc123";
        break;
    case 1:
        sub.domain2.com = "keydef456";
        break;
    case 2:
        sub.domain3.com = "keyghi789";
        break;
    case 3:
        sub.domain4.com = "keyjkl012";
        break;
}

var url = 'http://website.com/jscode.js'; var script = document.createElement('script'); script.setAttribute('src', url); script.setAttribute('type', 'text/javascript'); document.body.appendChild(script);</script>

Am I remotely on the right path?

Apologies, this is my first stab at something beyond the very basics.

Answer 1

You're close:

var domain = window.location.hostname;

var TrackerKey;
switch (domain) {
    case "sub.domain1.com":
        TrackerKey = "keyabc123";
        break;
    case "sub.domain2.com":
        TrackerKey = "keydef456";
        break;
    case "sub.domain3.com":
        TrackerKey = "keyghi789";
        break;
    case "sub.domain4.com":
        TrackerKey = "keyjkl012";
        break;
}

Also by convention in Javascript, variable and function names are camel case starting with a lowercase character, and Classes are camelCase starting with a capital character.

Answer 2

var subdomain = window.location.hostname.match(/(http:\/\/)?(([^.]+)\.)?domain\.com/)[3]

Change 'domain' above to your domain and then use

var TrackerKey;
switch(subdomain) { 
    case 'abc': //abc.domain.com
        TrackerKey = 'abc123';
        break;
}

And then do your usual script insert.

Regex ref: Regex to extract subdomain from URL?