How to detect if browser supports WebP format on server side PHP script?

We can make use of PHP global variable $_SERVER to do so.

Here’s another related post about PHP global variable $_SERVER.

How to get the full URL of current page in PHP?

Using $_SERVER[‘HTTP_ACCEPT’] we can get the detailed contents of the Accept: header, if there is one available.

Then we can use PHP strpos() function to check if it has image/webp in it. If so, it’s supported.

Here’s how we can do that:

if( strpos( $_SERVER['HTTP_ACCEPT'], 'image/webp' ) === true ) {
    // webp is supported!
}

Just change the true to false if you want to check if webp is not supported OR just use else in the previous example.

if( strpos( $_SERVER['HTTP_ACCEPT'], 'image/webp' ) === false ) {
    // webp is supported!
}

Use this code to check if webp is supported or the browser is chrome

if( strpos( $_SERVER['HTTP_ACCEPT'], 'image/webp' ) == true || strpos( $_SERVER['HTTP_USER_AGENT'], ' Chrome/' ) == true ) {
    // webp is supported!
}

Credit: Stack Overflow

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