[code]
<?php
    /*
    * @return boolean
    * @param  string $link
    * @desc   &#65533;berpr&#65533;ft die angegeben URL auf Erreichbarkeit (HTTP-Code: 200)
    */
    function url_validate( $link )
    {        
        $url_parts = @parse_url( $link );

        if ( empty( $url_parts["host"] ) ) return( false );

        if ( !empty( $url_parts["path"] ) )
        {
            $documentpath = $url_parts["path"];
        }
        else
        {
            $documentpath = "/";
        }

        if ( !empty( $url_parts["query"] ) )
        {
            $documentpath .= "?" . $url_parts["query"];
        }

        $host = $url_parts["host"];
        $port = $url_parts["port"];
        // Now (HTTP-)GET $documentpath at $host";

        if (empty( $port ) ) $port = "80";
        $socket = @fsockopen( $host, $port, $errno, $errstr, 30 );
        if (!$socket)
        {
            return(false);
        }
        else
        {
            fwrite ($socket, "HEAD ".$documentpath." HTTP/1.0\r\nHost: $host\r\n\r\n");
            $http_response = fgets( $socket, 22 );
            
            if ( ereg("200 OK", $http_response, $regs ) )
            {
                return(true);
                fclose( $socket );
            } else
            {
//                echo "HTTP-Response: $http_response<br>";
                return(false);
            }
        }
    }
?> 
[/code]