javascript/bookmarklet questions

Ok. I want to learn a little javascript so I can debug the following bookmarklet.

javascript:(function(){C=window.cookie.split("; ");
for(d="."+location.host;
d;
d=(""+d).substr(1).match(//..*$/))
for(sl=0;sl<2;++sl)
for(p="/"+location.pathname;
p;
p=p.substring(0,p.lastIndexOf('/')))
for(i in C)
if(c=C[i]){window.cookie=c+"; domain="+d.slice(sl)+";
path="+p.slice(1)+"/"+";
expires="+new Date((new Date).getTime()-1e11).toGMTString()}})();

alert('Cookies deleted')

I know that Safari (which is what I'm using) uses 'window' instead of 'document'. But I don't know why this bookmarklet isn't working. (It is supposed to make all the cookies from the site you are currently visiting expire.)

I've looked (briefly) for a place that simply defines all the objects and sub-objects and the commands that can be used on them in javascript, but I can't find one. (I don't even know if object, sub-object and command are the correct terms. They probably aren't. I mean the things like 'window' and 'window.cookie' and 'window.cookie.split', respectively.)

I'm not even sure I'm parsing the statement correctly. I don't know when the "for" statements end, or the "if" statements.

Any help? Where can I just find a simple definition of everything? Everywhere I go tries to give me a tutorial on javascript, which I don't want. I want something about bookmarklets.