Syntax error, unrecognized expression: unsupported pseudo

Question

Im trying to execute the following code below, but it throws the following error message:

Error: Syntax error, unrecognized expression: unsupported pseudo: really-good-at

The code:

<script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript">
    /* Implement a Cesar crypto decrypt for the code.
    * [Code ASCII] + n => Decrypted ASCII.
    * where n = char pos in cryptedCode string (R=1) */

if ($('.js.php.mysql.html.oop').is(':really-good-at')) {
    var cryptedCode = 'RFLLDN';
    var decryptedCode = '';
    console.log('Enter this code in the form: ' + decryptedCode);
    //Open website url
    var url = 'aHR0cDovL2JpdC5seS8xN21NRzk4';
    window.open(window.atob(url));
}
</script>
<input type="text" class="js.php.mysql.html.oop">

Anyone who can explain why this error is thrown?

Why are you using `:really-good-at` ? supported pseudos are `:empty, :checked` etc — Shaunak D, Jun 16 '14 at 07:12
@shaunakde: This is a code that I've found on a forum. Im trying to solve the crypto. So the :really-good-at are not supported? — user500468, Jun 16 '14 at 07:14
`:really-good-at` is invalid. What exactly are you trying to do? — Shaunak D, Jun 16 '14 at 07:15
@user500468 You should ask this question to that forum owners..! Closed as unclear..! — Rajaprabhu Aravindasamy, Jun 16 '14 at 07:15

score 17 · Accepted Answer · answered Jun 16 '14 at 07:20

17

You can see jQuery's list of valid selectors here: http://api.jquery.com/category/selectors/

Your problem is simply that :really-good-at is not a valid selector.

If really-good-at is a class name, you could use .is('.really-good-at')

answered Jun 16 '14 at 07:20

doctororange

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see here for proper **escaping helper code**: http://stackoverflow.com/a/3113742/1915920 – Andreas Covidiot Feb 18 '16 at 09:03

score 2 · Answer 2 · answered Jun 16 '14 at 07:17

Well, the error is clear...really-good-at is NOT a recognized css pseudo selector. You can't just use arbitrary pseudo selectors and expect it work. It's like me trying to speak Spanish in Japan and expecting japanese people to understand what I'm saying

score 0 · Answer 3 · answered Dec 12 '17 at 13:51

A very similar experience just happened to me with a pseudo selector that just didn't make sense. The problem is...it was in my own code!

This is how it was born: - initially it was a valid CSS expression: "td:nth-of-type" used within a callback function, so far so normal. Until I decided to select the whole of that function, and do a massive find/replace on the selected text: replace "type" with "action". Why? Because one of the arguments of that callback was wrongly named "type" instead of "action". This is how my pseudo selector ended up as "nth-of-action", hence triggering a JS error, which in turn stopped processing the rest of the code. As much as I know by experience that massive replaces are dangerous, I still reviewed my code to look for instances of "action", but I didn't see that the pseudo selector nth-of-type has been changed...

Syntax error, unrecognized expression: unsupported pseudo

3 Answers3