仅回显URL的一部分（字符串）

Question

I have an input field where the user can type an URL. He could type the URL in many different ways, for example:

• www.example.com
• http://example.com
• http://www.example.com
• example.com/index.php

No matter how he types it, I want to echo it like this: example.com

Only when it is an sub domain, then it should look like this: subdomain.example.com

How can I do this?

Answer 1

I allow myself to answer my own question:

$url = 'https://www.example.com/index.php';
$str = preg_replace('#^https?://|www.#', '', rtrim($url,'/'));
echo (strpos($str,'/') !== false) ? strstr($str, '/', true) : $str;

You can define $url however you want. The result is always example.com