可以检查User-Agent字符串。在JavaScript中，这很简单，它只是navigator对象的一个属性。

var useragent = navigator.userAgent;

你可以在JS中检查设备是iPhone还是黑莓

var isIphone = !!agent.match(/iPhone/i),
    isBlackberry = !!agent.match(/blackberry/i);

如果isIphone是真的，你是通过Iphone访问网站，如果是黑莓，你是通过黑莓访问网站。

你可以使用firefox的“UserAgent Switcher”插件来测试。

如果你也感兴趣，可能值得一试我的脚本“redirection_mobile.js”托管在github这里https://github.com/sebarmeli/JS-Redirection-Mobile-Site，你可以在我的一篇文章中阅读更多细节:

http://blog.sebarmeli.com/2010/11/02/how-to-redirect-your-site-to-a-mobile-version-through-javascript/

Just a thought but what if you worked this problem from the opposite direction? Rather than determining which browsers are mobile why not determine which browsers are not? Then code your site to default to the mobile version and redirect to the standard version. There are two basic possibilities when looking at a mobile browser. Either it has javascript support or it doesn't. So if the browser does not have javascript support it will default to the mobile version. If it does have JavaScript support, check the screen size. Anything below a certain size will likely also be a mobile browser. Anything larger will get redirected to your standard layout. Then all you need to do is determine if the user with JavaScript disabled is mobile or not. According to the W3C the number of users with JavaScript disabled was about 5% and of those users most have turned it off which implies that they actually know what they are doing with a browser. Are they a large part of your audience? If not then don't worry about them. If so, whats the worst case scenario? You have those users browsing the mobile version of your site, and that's a good thing.

你还没说你在用什么语言。如果是Perl，那么它很简单:

use CGI::Info;

my $info = CGI::Info->new();

if($info->is_mobile()) {
   # Add mobile stuff
}

unless($info->is_mobile()) {
   # Don't do some things on a mobile
}

您可以通过导航器简单地检测移动客户机。并根据检测到的客户端类型加载备用脚本，如下所示:

 $(document).ready(function(e) {

        if(navigator.userAgent.match(/Android/i)
          || navigator.userAgent.match(/webOS/i)
          || navigator.userAgent.match(/iPhone/i)
          || navigator.userAgent.match(/iPad/i)
          || navigator.userAgent.match(/iPod/i)
          || navigator.userAgent.match(/BlackBerry/i)
          || navigator.userAgent.match(/Windows Phone/i)) {

         //write code for your mobile clients here.

          var jsScript = document.createElement("script");
          jsScript.setAttribute("type", "text/javascript");
          jsScript.setAttribute("src", "js/alternate_js_file.js");
          document.getElementsByTagName("head")[0].appendChild(jsScript );

          var cssScript = document.createElement("link");
          cssScript.setAttribute("rel", "stylesheet");
          cssScript.setAttribute("type", "text/css");
          cssScript.setAttribute("href", "css/alternate_css_file.css");
          document.getElementsByTagName("head")[0].appendChild(cssScript); 

    }
    else{
         // write code for your desktop clients here
    }

    });

protected void Page_Load(object sender, EventArgs e)
{
    if (Request.Browser.IsMobileDevice == true)
    {
        Response.Redirect("Mobile//home.aspx");
    }
}

这个例子在asp.net中工作

我最喜欢的移动浏览器检测机制是WURFL。它经常更新，适用于每一个主要的编程/语言平台。