title: php preg_replace how not changing urls
body: <p><strong>ts</strong> in html content should be replaced by <strong>s.</strong></p>
  <p>for example:
  <code>sanktsya</code> =&gt; <code>sanksya</code></p>
  <p>That's how it works fine.</p>
  <p>But <code>a</code> or <code>img</code> <code>urls</code> are changing.</p>
  <p><strong>how to not changing urls ?</strong></p>
  <p><strong>My code</strong></p>
  <pre><code>$str='&lt;p&gt;sanktsya boshlandi.&lt;/p&gt;
  &lt;p&gt;&lt;img src=&quot;https://img.com/Sqstso.jpeg&quot; /&gt;&lt;/p&gt;';
  
  $result = preg_replace(&quot;/([qwrtpsdfghklzxcvbnmQWRTPSDFGHKLZXCVBNM]+)[tT]s/&quot;, &quot;\${1}s&quot;, $str);
  </code></pre>