Can you use term_exists from with in Javascript loop?

I have a Javascript in the function.php file, that works well to generate a part code.

When I try to add the code to a taxonomy, I get an error saying that:

Error: term_exists is not defined

It comes from this if statement in the script:

// Add Code to taxonomy
                if (term_exists(code, wheel_type)) {
                     alert(code);
                     }
                else
                     {
                     wp_insert_term(code, wheel_type);
                     }

Can anyone tell me what I did wrong, or how to add a term to a taxonomy from with in a Javascript section?