strip_tags
Remove HTML and PHP tags from string
Strip HTML tags from strings:
<span class="token php language-php"><span class="token delimiter important"><?php</span> <span class="token keyword">echo</span> <span class="token function">strip_tags</span> <span class="token punctuation">(</span> <span class="token string double-quoted-string">"Hello <b>world!</b>"</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token delimiter important">?></span></span>
Strip the HTML tags from the string, but allow the <b> tags:
<span class="token php language-php"><span class="token delimiter important"><?php</span> <span class="token keyword">echo</span> <span class="token function">strip_tags</span> <span class="token punctuation">(</span> <span class="token string double-quoted-string">"Hello <b><i>world!</i></b>"</span> <span class="token punctuation">,</span> <span class="token string double-quoted-string">"<b>"</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token delimiter important">?></span></span>