Solution

The function strip_tags() does completely get rid of all HTML elements. If you just want to keep some elements (for example, some limited formatting functionalities with <b> and <i> and <br /> tags), you provide a list of allowed values in the second parameter for strip_tags().

<?php
$input = 'The term <i>Official Ireland</i> is commonly <br />' .
	'used in  <b>the Republic of Ireland</b> to denote<br />' .
	' the media, cultural and religious establishment. '.
	'<script>alert("Nice try!");</script>' .
	'<img src="/spam.jpg" />';
	
echo strip_tags($input, '<b><br><i>');
?>

Output of the above code

The term Official Ireland is commonly 
used in  the Republic of Ireland to denote
the media, cultural and religious establishment. alert("Nice try!");