Hash_hmac (PHP) vs hex_hmac_sha1 (Javascript)

I'm new here and I have a question.

Could you please tell me why hex_hmac_sha1 (function in Javascript) is not working and also hash_hmac (function in PHP).

If it is Az it means that everything is ok, but it is not ok for other characters.

For example:

Javascript

<script type="text/javascript" src="https://online.ingbank.pl/mobi/js/sha1.js"></script>
<script>
document.write(hex_hmac_sha1("1492343027",'a')+"<br />");
document.write(hex_hmac_sha1("1492343027",'ą')+"<br />");
document.write(hex_hmac_sha1("1492343027",'c')+"<br />");
document.write(hex_hmac_sha1("1492343027",'ć')+"<br />");
</script>

      

        
        
        
      

    

output:

f75d4cbfbfda2476a9c92fff10fdf0e726ee06ab
206e608ecaf23a9575ca81a86e3afd72eca243a0
73e0dc1dd914b1386a5f2624883caad41025da07
86dc107aac5cb5c17a846defd651a3eb53d66a44

      

        
        
        
      

    

PHP

echo hash_hmac("sha1", 'a', "1492343027").'<br />'; 
echo hash_hmac("sha1", 'ą', "1492343027").'<br />'; 
echo hash_hmac("sha1", 'c', "1492343027").'<br />'; 
echo hash_hmac("sha1", 'ć', "1492343027").'<br />'; 

      

        
        
        
      

    

output:

f75d4cbfbfda2476a9c92fff10fdf0e726ee06ab
8b353bb4c891d73ae9be09d0653e2564e0dff243
73e0dc1dd914b1386a5f2624883caad41025da07
52278a6e8676e8f3c667082411cfa04519c4bab1

      

        
        
        
      

    

This is fine for 'a' and 'c', but what happens with '±' and 'ć'?

thanks for the help