Title: wpdb::check_ascii
Published: April 23, 2015
Last modified: May 20, 2026

---

# wpdb::check_ascii( string $input_string ): bool

## In this article

 * [Description](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#description)
 * [Parameters](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#wp--skip-link--target)

Checks if a string is ASCII.

## 󠀁[Description](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#description)󠁿

The negative regex is faster for non-ASCII strings, as it allows the search to finish
as soon as it encounters a non-ASCII character.

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#parameters)󠁿

 `$input_string`stringrequired

String to check.

## 󠀁[Return](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#return)󠁿

 bool True if ASCII, false if not.

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#source)󠁿

    ```php
    protected function check_ascii( $input_string ) {
    	if ( function_exists( 'mb_check_encoding' ) ) {
    		if ( mb_check_encoding( $input_string, 'ASCII' ) ) {
    			return true;
    		}
    	} elseif ( ! preg_match( '/[^\x00-\x7F]/', $input_string ) ) {
    		return true;
    	}

    	return false;
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/class-wpdb.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/class-wpdb.php#L3463)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/class-wpdb.php#L3463-L3473)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#related)󠁿

| Used by | Description | 
| [wpdb::check_safe_collation()](https://developer.wordpress.org/reference/classes/wpdb/check_safe_collation/)`wp-includes/class-wpdb.php` |

Checks if the query is accessing a collation considered safe.

  | 
| [wpdb::strip_invalid_text()](https://developer.wordpress.org/reference/classes/wpdb/strip_invalid_text/)`wp-includes/class-wpdb.php` |

Strips any invalid characters based on value/charset pairs.

  | 
| [wpdb::query()](https://developer.wordpress.org/reference/classes/wpdb/query/)`wp-includes/class-wpdb.php` |

Performs a database query, using current database connection.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wpdb/check_ascii/?output_format=md#changelog)󠁿

| Version | Description | 
| [4.2.0](https://developer.wordpress.org/reference/since/4.2.0/) | Introduced. |

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