100% working this code
<a id="button" class="instagram-token-button" href="https://api.instagram.com/oauth/authorize/?client_id=CLIENT_ID&redirect_uri=REDIRECT_URL&response_type=code">Click here to get your Instagram Access Token and User ID</a>
<?PHP
if (isset($_GET['code'])) {
$code = $_GET['code'];
$client_id='< YOUR CLIENT ID >';
$redirect_uri='< YOUR REDIRECT URL >';
$client_secret='< YOUR CLIENT SECRET >';
$url='https://api.instagram.com/oauth/access_token';
$request_fields = array(
'client_id' => $client_id,
'client_secret' => $client_secret,
'grant_type' => 'authorization_code',
'redirect_uri' => $redirect_uri,
'code' => $code
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
$request_fields = http_build_query($request_fields);
curl_setopt($ch, CURLOPT_POSTFIELDS, $request_fields);
$results = curl_exec($ch);
$results = json_decode($results,true);
$access_token = $results['access_token'];
echo $access_token;
exit();
}
?>