Checks (category)

is_admin_bar_showing()

Determine whether the admin bar should be showing.

is_blog_installed()

Test whether WordPress is already installed.

is_countable()

Polyfill for is_countable() function added in PHP 7.3.

is_email()

Verifies that an email is valid.

is_iterable()

Polyfill for is_iterable() function added in PHP 7.1.

is_php_version_compatible()

Checks compatibility with the current PHP version.

is_serialized()

Check the given value if it's a serialized string.

is_serialized_string()

Check whether serialized data is of string type.

is_wp_error()

Checks whether the passed variable is a WordPress Error.

is_wp_version_compatible()

Checks compatibility with the current WordPress version.

seems_utf8()

Checks to see if a string is UTF-8 encoded.

wp_doing_ajax()

Determines whether the current request is a WordPress Ajax request.

wp_is_https_supported()

Checks whether HTTPS is supported for the server and domain.

wp_is_json_request()

Checks whether current request is a JSON request, or is expecting a JSON response.

wp_is_numeric_array()

Checks if the specified variable is an numeric-indexed array.

wp_is_using_https()

Checks whether the website is using HTTPS.

wp_validate_boolean()

Turns the value of the specified variable into a logical true or false.