<head>
<meta charset="<?php bloginfo( 'charset' ); ?>">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="profile" href="http://gmpg.org/xfn/11">
<?php
if (is_single()){
//add more keywords in regex code
$badWords = array("badwords","badkeyword");
$string = get_the_content();
$matches = array();
$matchFound = '';
$matchFound = preg_match_all("/\b(" . implode($badWords,"|") . ")\b/i",$string,$matches);
}
?>
<meta name="robots" content="index,follow <?php echo $matchFound ?>" />
<?php wp_head() ?>
</head>
