I'm trying to show jpg in browsers that don't support webp without using a plugin,

When uploading images, I upload both as webp and jpg.

İ add webp by default, I need to change the extension to .jpg when entered from a browser that does not support webp, i found a php code about it but my attempts were unsuccessful.

if (strpos( $_SERVER['HTTP_ACCEPT'], 'image/webp' ) !== false) {
  //do nothing when webp is supported
} else {
  //.webp replace .jpg
  • Your not equal is incorrect. != is NOT EQUAL, where as == is EQUAL and === is identical, meaning if you try to match 1 (string) to 1 (integer) the === will return false, but if you use == it will return true. w3schools.com/php/php_operators.asp Feb 7 at 14:20

1 Answer 1


I think the best way to filter out the browsers for supporting webp is to do it on client-side width html element or Javascript, not with php on the server-side.

If you want to do it by php you need to look at:


That will contain the User-Agent string for the browser. Beware that almost all browsers claim to be "Mozilla" for compatibility reasons - you need to look for specific text for each browser within that header, eg. "MSIE" for Internet Explorer.


My Firefox calls itself Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv: Gecko/2009060215 Firefox/3.0.11 (.NET CLR 4.0.20506)

My IE7 calls itself Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; GTB6; User-agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; http://bsalsa.com) ; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 4.0.20506)

or use get_browser() php function.

Example from Manual:

echo $_SERVER['HTTP_USER_AGENT'] . "\n\n";
$browser = get_browser(null, true);

Will return:

    [browser_name_regex] => ^mozilla/5\.0 (windows; .; windows nt 5\.1; .*rv:.*) gecko/.* firefox/0\.9.*$
    [browser_name_pattern] => Mozilla/5.0 (Windows; ?; Windows NT 5.1; *rv:*) Gecko/* Firefox/0.9*/
    [parent] => Firefox 0.9
    [platform] => WinXP
    [browser] => Firefox
    [version] => 0.9
    [majorver] => 0
    [minorver] => 9
    [cssversion] => 2
    [frames] => 1
    [iframes] => 1
    [tables] => 1
    [cookies] => 1
    [backgroundsounds] =>
    [vbscript] =>
    [javascript] => 1
    [javaapplets] => 1
    [activexcontrols] =>
    [cdf] =>
    [aol] =>
    [beta] => 1
    [win16] =>
    [crawler] =>
    [stripper] =>
    [wap] =>
    [netclr] =>

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