How to replace a line in a script using php?

Question

PHP

Good day!
There is a widget from Facebook (Page), how to make the user register on the site, indicate his ID to the group during registration, throw the ID into the database, and the widget code itself, take the ID from this very database and substitute it instead of the original one?

<div class="fb-page" data-href="https://www.facebook.com/facebook" data-tabs="timeline" data-small-header="false" data-adapt-container-width="true" data-hide-cover="false" data-show-facepile="true"><blockquote cite="https://www.facebook.com/facebook" class="fb-xfbml-parse-ignore"><a href="https://www.facebook.com/facebook">Facebook</a></blockquote></div>

Answer 1

<?php
  $from    = array('%id%', '%group%', '%etc%');
  $to      = array(1, 43, 'smth');
  $str     = 'https://facebook.com/...?id=%id%&group=%group%&etc=%etc%';
  $str     = str($from, $to, $str);