Validate URL in PHP with RegExp.

verfiURL.php

<?php
    
    /* === URL validation
     *     [scheme] hostname [path] [file[getquery]] [#anchor]
     *     http://example.com/test/user.php?id=1234#details
     */

    function validURL($url){
        
        /* --- Scheme
         *     http://, https:// or nothing.
         */
    
        $regexURL = '((https?)\:\/\/)?';
        
        /* --- Hostname
         *     domain and sub-domain with a minimum of 2 characters.
         *     top-domain 2 or 3 characters.
         *     example.com, example.ca, example.gov.ca, shop.example.com, test-site.example.com, etc.
         */
    
        $regexURL .= '(\w{2,}\.)+[a-zA-Z]{2,3}';
    
        /* --- Path
         *     folder path
         *     /, or /test, /test/, /test/awesome, /test/awesome/
         */
    
        $regexURL .= '((\/[\w+-]+)*\/?)?';
    
         /* --- File
         *   - Check up the last element of the file if it's a file.
         *     file.extension
         *   - GET query
         *     ?user=123&name=Yohann%20Paris&class=test::cool
         */
    
        $regexURL .= '([\w-]+\.\w{2,}(\?[\w+\&\$-][\w;:@\&%=+\$-]*)?)?';
        
        /* --- Anchor
         *     #, #title, #cool-Title
         */
    
        $regexURL .= '(#[\w-]*)?';    
    
        /* --- Validate the entirely URL */
        
        $regexURL = '/^'.$regexURL.'$/';
     
        return preg_match($regexURL, $url);
    }