How to remove everything superfluous from the text, and leave only the tags?

Question

PHP

In addition to the usual
<script>Вредоносный код</script>
, Users can stuff things like this
<div onclick="Вредоносный код"></div>
. How to remove everything unnecessary from the test (js, flash, something else that can harm the user) and allow tags with styles to be left in the test
. Example:

<h1>Заголовок</h1>
<div style="color:#ffffff;border: 1px solid #b6c2c9;background: #b6c2c9;">Текст</div>
<b style="color:#000000;"><i>Подпись</i></b>

Answer 1

strip_tags

<?php

$text = '<p>Параграф.</p><!-- Комментарий --> <a href="#fragment">Еще текст</a>';

// Разрешаем <p> и <a>
echo strip_tags($text, '<p><a>');

https://habrahabr.ru/company/smartprogress/blog/202188htmlpurifier.org
UPD
https://github.com/imangazaliev/didom

foreach($document->find('*[onclick]') as $element) {
    $element->removeAttribute('onclick');
}