How to detect an HTML code is phishing using php?

I have some html code stored in a variable say $htmlcode. before the code is echoed i need to check if it is phishing or not. Else Chrome will warn all users the site is deceptive, during indexing.

<?php
$htmlcode= "<h2>Heading</h2><br><p>this is a paragraph</p>";
echo $htmlcode ;
?>

The $htmlcode code is got from users. If they create an Html code that fake login page of popular sites like Facebook, twitter. Login details will be vulnerable.

I want to prevent those. Is there any API to detect such things?