WordPress – Add target=”_blank” to content

Add the following code to your functions.php file:

/*
 * Add target blank to content links
 */
function wp_add_target_blank($content) {
	// Get the site url
	$site_url = get_site_url();
	
	// Get all the links in the article
	preg_match_all('#<a ([^>]*)>#i', $content, $matches);
	
	// Loop through each link
	foreach ($matches[1] as $key=>$value)
	{
		// If link does not contain the site_url or the text _blank, add target="_blank"
		if (!stristr($value, $site_ul) && !stristr($value, '_blank'))
		{
			$content = str_replace('<a '.$value.'>', '<a target="_blank" '.$value.'>', $content);
		}
	}
	// Return the modified content
	return $content;
}

// Add the wordpress filter
add_filter( 'the_content', 'wp_add_target_blank' );