script to detect mobile or smaller screen

[BillTheBuilder]

I am trying to put a script into the head of my site and have it automatically detect a mobile or screen size from the browser and redirect to a mobile friendly page.

I am using

<script type="text/javascript"> 
if(screen.width < 600){ 
window.location = "http://www.sigl.ws/Phone_Page.html"; 
} 
</script>

I built a small test site to try it out at www.sigl.ws. It is nothing fancy and not a real site. It is strictly to test this script. The main page shows a laptop and the only two buttons that work are home and phone to see what the mobile page would look like.

I cannot get it work with my android. What am I doing wrong?

Thanks

Edited----

I did try another script and it redirects great. Besides now building a smaller page to view, a new issue popped up on how to allow a mobile user view the main site without getting caught in a loop. I would also like to do this without a duplicate home page. The script I used was:

     <script type="text/javascript">// <![CDATA[  
        var mobile = (/iphone|ipad|ipod|android|blackberry|mini|windows\sce|palm/i.test(navigator.userAgent.toLowerCase()));  
        if (mobile) {  
            document.location = "http://www.mysitename.com/Phone_Page.html";  
        }  
    // ]]></script>

Thoughts?

[DNSBL]

And maybe this might help you understand..

detectmobilebrowsers.com

[BillTheBuilder]

Thanks for the link.

I now have the loop taken care of. I am not really versed on CSS yet and so built a small site sized for an android phone for the mobile user to land on, but not kindles or ipads and be able to get back to the main site.

[EffEss]

BilltheBuilder, I am using the same redirect code as you but I'm having a terrible time with the loop part. Can you please post the code you used?