<div>
<img src="//example.com/relative/url/img.jpg">
<form action="//example.com/"></form>
<form action="//example.com/contact-us/"></form>
<a href="//example.com/relative/url/">Note the Single Quote</a>
<img src="//example.com/protocol-relative-img.jpg">
</div>
Output for 8.3.5
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
<div>
<img src="//example.com/relative/url/img.jpg">
<form action="//example.com/"></form>
<form action="//example.com/contact-us/"></form>
<a href="//example.com/relative/url/">Note the Single Quote</a>
<img src="//example.com/protocol-relative-img.jpg">
</div>