Mobile index not redirecting to index for appropriate device (desktop or tablet)

Question

When a user shares my website from their phone browser and another user clicks the link from a tablet or desktop, it still shows the phone version.  For instance:
My son shares the website using the share feature on his android phone.  No matter WHERE he is sharing through (messages, email, facebook, twitter, etc), the link shared is http://truehdfitness.com/phone/index.html.  Muse places all redirect scripts on the desktop version of the site, but I need to be able to redirect people who click that link from a tablet or a tablet.  I've already had to export the website to dreamweaver to tackle a few code issues, I just need to know what to add to my tablet and phone pages to get them to redirect according to device when shared links are clicked.
As you can see, I've shared the page from both desktop and mobile to my facebook page.  I had hope that by changing the og url it would link to my desktop page, but that isn't the case.  It still links to the phone index, which means the only people that see the site like they should are those who click that link from a mobile phone.  This won't do!  Too many people share pages these days and statistics show that many people start viewing a page from one device and go back to it through a different device.  Mobile and tablet links HAVE to redirect to appropriate sites.
If you'd like to see what I'm talking about, click the topmost post on my facebook timeline while you're on a desktop or tablet.  It's UGLY!  https://www.facebook.com/dedi.thorne
So, is there code that I can add to my phone and tablet sites that will resolve this?
Thanks!
Dedi

Answer 1

<script language="javascript">
var mobile = (/iphone|ipad|ipod|android|blackberry|mini|windows\sce|palm/i.test(navigator.userAgent.to LowerCase()));
if (!mobile) {
var filename = location.pathname.substr(location.pathname.lastIndexOf("/")+1);
              window.location.replace("http://ThorneHills.com/index.html");
</script>
This is what I tried on http://www.thornehills.com/phone/index.html
Did I misunderstand how I was supposed to put the pagename in?  I wasn't sure what you were saying, so I looked at the javascript site and that's what I came up with.add that
Edited to add that I had honestly tried it several times and finally gave up and came back to you for clarification.  The code I posted is just my most recent attempt.