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php detect browser version HTTP_USER_AGENT

问题描述:

I try to detect the browser version in order to detect if the current browser is Internet Explorer version superior or egual to 8.

However it seems to doesn't work and I've got this error (in Firefox and sometimes in Google Chrome):

Undefined index: HTTP_USER_AGENT in

Here is my code:

 preg_match('/MSIE (.*?);/', $_SERVER['HTTP_USER_AGENT'], $matches);

if(count($matches)<2){

preg_match('/Trident\/\d{1,2}.\d{1,2}; rv:([0-9]*)/', $_SERVER['HTTP_USER_AGENT'], $matches);

}

if (count($matches)>1){

$version = $matches[1];

} else {

$version = 999;

}

if($version >= 9) {

wp_enqueue_script('preloader');

}

网友答案:
Undefined index: HTTP_USER_AGENT

This error message indicates that the request you're dealing with contained no User-Agent header at all, so the HTTP_USER_AGENT key isn't present in $_SERVER. There's no way to figure out what browser was involved from PHP, because the browser hasn't identified itself. (It's quite possible that it wasn't a web browser at all.)

网友答案:

None of the get_browser alternatives output the correct name / version combination that I was looking for using Opera or Chrome. They either give the wrong name eg Safari when in fact it should be Chrome and if the ua string includes a version number as with the latest versions of Chrome and Opera the wrong number is reported. Here is a function that can check for version.

<?php
function getBrowser() 
{ 
    $u_agent = $_SERVER['HTTP_USER_AGENT']; 
    $bname = 'Unknown';
    $platform = 'Unknown';
    $version= "";

    //First get the platform?
    if (preg_match('/linux/i', $u_agent)) {
        $platform = 'linux';
    }
    elseif (preg_match('/macintosh|mac os x/i', $u_agent)) {
        $platform = 'mac';
    }
    elseif (preg_match('/windows|win32/i', $u_agent)) {
        $platform = 'windows';
    }

    // Next get the name of the useragent yes seperately and for good reason
    if(preg_match('/MSIE/i',$u_agent) && !preg_match('/Opera/i',$u_agent)) 
    { 
        $bname = 'Internet Explorer'; 
        $ub = "MSIE"; 
    } 
    elseif(preg_match('/Firefox/i',$u_agent)) 
    { 
        $bname = 'Mozilla Firefox'; 
        $ub = "Firefox"; 
    } 
    elseif(preg_match('/Chrome/i',$u_agent)) 
    { 
        $bname = 'Google Chrome'; 
        $ub = "Chrome"; 
    } 
    elseif(preg_match('/Safari/i',$u_agent)) 
    { 
        $bname = 'Apple Safari'; 
        $ub = "Safari"; 
    } 
    elseif(preg_match('/Opera/i',$u_agent)) 
    { 
        $bname = 'Opera'; 
        $ub = "Opera"; 
    } 
    elseif(preg_match('/Netscape/i',$u_agent)) 
    { 
        $bname = 'Netscape'; 
        $ub = "Netscape"; 
    } 

    // finally get the correct version number
    $known = array('Version', $ub, 'other');
    $pattern = '#(?<browser>' . join('|', $known) .
    ')[/ ]+(?<version>[0-9.|a-zA-Z.]*)#';
    if (!preg_match_all($pattern, $u_agent, $matches)) {
        // we have no matching number just continue
    }

    // see how many we have
    $i = count($matches['browser']);
    if ($i != 1) {
        //we will have two since we are not using 'other' argument yet
        //see if version is before or after the name
        if (strripos($u_agent,"Version") < strripos($u_agent,$ub)){
            $version= $matches['version'][0];
        }
        else {
            $version= $matches['version'][1];
        }
    }
    else {
        $version= $matches['version'][0];
    }

    // check if we have a number
    if ($version==null || $version=="") {$version="?";}

    return array(
        'userAgent' => $u_agent,
        'name'      => $bname,
        'version'   => $version,
        'platform'  => $platform,
        'pattern'    => $pattern
    );
} 

// now try it
$ua=getBrowser();
$yourbrowser= "Your browser: " . $ua['name'] . " " . $ua['version'] . " on " .$ua['platform'] . " reports: <br >" . $ua['userAgent'];
print_r($yourbrowser);
?>
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