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Function Reference/get option('siteurl')

This function has been deprecated. That means it has been replaced by a new function or is no longer supported, and may be removed from future versions. All code that uses this function should be converted to use its replacement if one exists. See also wp-includes/deprecated.php. Use any of these functions instead.

Please use the site_url() function for equivalent functionality.

Though the WordPress PHP deprecation notice recommends use of get_option('url') to replace this, it is *not* equivalent. get_option('url') does not include the subdirectory in the returned URL though get_option('site_url') does.