我们可以通过如下一个函数来判断是否是使用手机访问网站：
function is_mobile(){
$user_agent = $_SERVER['HTTP_USER_AGENT'];
$mobile_agents = Array("240x320","acer","acoon","acs-","abacho","ahong","airness","alcatel","amoi","android","anywhereyougo.com","applewebkit/525","applewebkit/532","asus","audio","au-mic","avantogo","becker","benq","bilbo","bird","blackberry","blazer","bleu","cdm-","compal","coolpad","danger","dbtel","dopod","elaine","eric","etouch","fly ","fly_","fly-","go.web","goodaccess","gradiente","grundig","haier","hedy","hitachi","htc","huawei","hutchison","inno","ipad","ipaq","ipod","jbrowser","kddi","kgt","kwc","lenovo","lg ","lg2","lg3","lg4","lg5","lg7","lg8","lg9","lg-","lge-","lge9","longcos","maemo","mercator","meridian","micromax","midp","mini","mitsu","mmm","mmp","mobi","mot-","moto","nec-","netfront","newgen","nexian","nf-browser","nintendo","nitro","nokia","nook","novarra","obigo","palm","panasonic","pantech","philips","phone","pg-","playstation","pocket","pt-","qc-","qtek","rover","sagem","sama","samu","sanyo","samsung","sch-","scooter","sec-","sendo","sgh-","sharp","siemens","sie-","softbank","sony","spice","sprint","spv","symbian","tablet","talkabout","tcl-","teleca","telit","tianyu","tim-","toshiba","tsm","up.browser","utec","utstar","verykool","virgin","vk-","voda","voxtel","vx","wap","wellco","wig browser","wii","windows ce","wireless","xda","xde","zte");
$is_mobile = false;
foreach ($mobile_agents as $device) {
if (stristr($user_agent, $device)) {
$is_mobile = true;
break;
}
}
return $is_mobile;
}
但是，这个函数有一个该死的问题，那就是ipad！我们一般都设置了如果是使用手机来访问网站，系统会自动跳转到一个手机网站上。但如果是ipad访问呢？我想大部分人还是希望网站仍然显示PC站的内容吧。但这个函数，很明显把ipad也算作了手机端。
其实参照百度的uaredirect函数，完全可以把$mobile_agents数组简写成"iphone"和"android"两个值就可以了！