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wp_check_jsonp_callback() WP 4.6.0

Checks that a JSONP callback is a valid JavaScript callback.

Only allows alphanumeric characters and the dot character in callback function names. This helps to mitigate XSS attacks caused by directly outputting user input.

No Hooks.


true/false. True if valid callback, otherwise false.


wp_check_jsonp_callback( $callback );
$callback(string) (required)
Supplied JSONP callback function.

Code of wp check jsonp callback: wp-includes/functions.php WP 5.2.2

function wp_check_jsonp_callback( $callback ) {
	if ( ! is_string( $callback ) ) {
		return false;

	preg_replace( '/[^\w\.]/', '', $callback, -1, $illegal_char_count );

	return 0 === $illegal_char_count;