在使用浏览器发起的 HTTP 请求中，通常会包含一个识别标识。它名为 User Agent，简称 UA。它是一串包含了客户端基础信息的字符串。通过它可以方便的获取客户端的操作系统，语言，浏览器和版本信息。
1、获取UA标识
echo $_SERVER['HTTP_USER_AGENT'];
结果：
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36
根据得到的字符串匹配出访问方式 但是手机系统很多种
2、封装方法进行判断
if (!function_exists("isMobile")) {function isMobile(){$user_agent = $_SERVER['HTTP_USER_AGENT'];$mobile_agents = array ('iphone','android','phone','mobile','wap','netfront','java','opera mobi','opera mini','ucweb','windows ce','symbian','series','webos','sony','blackberry','dopod','nokia','samsung','palmsource','xda','pieplus','meizu','midp','cldc','motorola','foma','docomo','up.browser','up.link','blazer','helio','hosin','huawei','novarra','coolpad','techfaith','alcatel','amoi','ktouch','nexian','ericsson','philips','sagem','wellcom','bunjalloo','maui','smartphone','iemobile','spice','bird','zte-','longcos','pantech','gionee','portalmmm','jig browser','hiptop','benq','haier','^lct','320x320','240x320','176x220','windows phone','cect','compal','ctl','lg','nec','tcl','daxian','dbtel','eastcom','konka','kejian','lenovo','mot','soutec','sgh','sed','capitel','panasonic','sonyericsson','sharp','panda','zte','acer','acoon','acs-','abacho','ahong','airness','','applewebkit/525','applewebkit/532','asus','audio','au-mic','avantogo','becker','bilbo','bleu','cdm-','danger','elaine','eric','etouch','fly ','fly_','fly-','go.web','goodaccess','gradiente','grundig','hedy','hitachi','htc','hutchison','inno','ipad','ipaq','ipod','jbrowser','kddi','kgt','kwc','lg ','lg2','lg3','lg4','lg5','lg7','lg8','lg9','lg-','lge-','lge9','maemo','mercator','meridian','micromax','mini','mitsu','mmm','mmp','mobi','mot-','moto','nec-','newgen','nf-browser','nintendo','nitro','nook','obigo','palm','pg-','playstation','pocket','pt-','qc-','qtek','rover','sama','samu','sanyo','sch-','scooter','sec-','sendo','sgh-','siemens','sie-','softbank','sprint','spv','tablet','talkabout','tcl-','teleca','telit','tianyu','tim-','toshiba','tsm','utec','utstar','verykool','virgin','vk-','voda','voxtel','vx','wellco','wig browser','wii','wireless','xde','pad','gt-p1000');$ismobile = false;foreach ($mobile_agents as $device) {if (stristr($user_agent, $device)) {$ismobile = true;break;}}return $ismobile;}}
这样直接判断方法的返回值就可以直接判断是pc还是移动
