How to include jQuery when no header and footer on the page

Though uncommon, you can use wp_print_scripts( ['jquery'] ) for explicit output.

Note that you might hit issues with hooks firing in unexpected ways and such. Generally all WP pages on front end should just implement header/footer properly.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)