PHP determines whether a GIF image is a dynamic picture (animated) method

How do I use PHP to determine if a GIF picture is a dynamic picture (animation)?

The first thought is that using the getimagesize () function to look at the type value is GIF, so this approach is not feasible.

Here is a function that the author sees on the Internet to determine whether GIF is a dynamic graph. Post it and share it with you.

/*
* Determine if the picture is a dynamic picture (animation)
*/
function Isanimatedgif ($filename) {
$FP =fopen ($filename, ' RB ');
$filecontent =fread ($fp, FileSize ($filename));
Fclose ($FP);
Return Strpos ($filecontent, Chr (0x21). chr (0xff). chr (0x0b). NETSCAPE2.0 ') ===false?0:1;
}

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