Javascript useragent detection

[Hicks12]

Building a website based on a report i had to do, one key element was the use of mobile devices, ive been trying for a good couple of hours now and im still unable todo it for some reason, it doesnt need to be perfect (for example opera mobile etc doesnt need to be supported, just iphone/ipad and Android stock).

All i need todo is use javascript (or an alternative method if someone knows a way?) to detect the browser and if its one of the mobile ones then redirect to the mobilesite.htm. It seems everthing i do is ignored via my O2x on the stock browser, looking at websites which show how todo this it works fine but as soon as i try and implement it I cant get it working!. Now it maybe that im a bit tired after working but was just wondering if someone could point me in the right direction?

the main way i tried was:
<script type="text/javascript"> <![CDATA[
var mobile = (/iphone|ipad|ipod|android|blackberry|mini|windows\sce|palm/i.test(navigator.userAgent.toLowerCase()));
if (mobile) {
window.open('mobilesite.htm')
}
]]></script>
(also tried with document.location = "mobilesite.htm"; )

Am i just being an idiot here?

[Lucio]

Just to check, on my phone (HTC Desire), I have an option to ignore mobile browser redirects. Make sure that isn't enabled on your test device

[Hicks12]

Just noticed this is in the wrong place >.<, if a mod wants to move it then please do.

Yeah ive made sure that is set up properly Lucio, its odd as when I look at websites which use the exact same code, it works and gives a correct output but when i try and implement it there seems to be an issue . Odd!

[finlay666]

http://www.quirksmode.org/js/detect.html

pretty sure your user agents are wrong there though, should be looking in the whole string (tried printing out the given user agent? Mine only says Android on line 4 (Mozilla pops up first)

I suggest you go with a premade library
http://detectmobilebrowsers.com/

The thing that should actually be considered is the rendering capabilities though, a lot of sites that I use on my phone see android and force flash objects where as on an iphone they opt for html 5 objects, even changing the UA string to that of an iPhone doesn't change this (impersonation should fail IMO as it's better practice to check if the browser can render something than to assume based on a subset), main one being video players