Java Cookie Help!

[Silvers24]

ok, i found the coding I need, but I have no damn clue how to edit it! Or what to edit more put.
First up the Java Script. I know how to save it, but I need to know what to edit.

var expDays = 30;
var exp = new Date();
exp.setTime(exp.getTime() + (expDays*24*60*60*1000));

function getCookieVal (offset) {
var endstr = document.cookie.indexOf (";", offset);
if (endstr == -1)
endstr = document.cookie.length;
return unescape(document.cookie.substring(offset, endstr));
}
function GetCookie (name) {
var arg = name + "=";
var alen = arg.length;
var clen = document.cookie.length;
var i = 0;
while (i < clen) {
var j = i + alen;
if (document.cookie.substring(i, j) == arg)
return getCookieVal (j);
i = document.cookie.indexOf(" ", i) + 1;
if (i == 0) break;
}
return null;
}
function SetCookie (name, value) {
var argv = SetCookie.arguments;
var argc = SetCookie.arguments.length;
var expires = (argc > 2) ? argv[2] : null;
var path = (argc > 3) ? argv[3] : null;
var domain = (argc > 4) ? argv[4] : null;
var secure = (argc > 5) ? argv[5] : false;
document.cookie = name + "=" + escape (value) +
((expires == null) ? "" : ("; expires=" + expires.toGMTString())) +
((path == null) ? "" : ("; path=" + path)) +
((domain == null) ? "" : ("; domain=" + domain)) +
((secure == true) ? "; secure" : "");
}
function DeleteCookie (name) {
var exp = new Date();
exp.setTime (exp.getTime() - 1);
var cval = GetCookie (name);
document.cookie = name + "=" + cval + "; expires=" + exp.toGMTString();
}

var favorite = GetCookie('animal');

if (favorite != null) {
switch (favorite) {
case 'cat' : 	url = 'cat.html'; // change these!
	     	break;
case 'dog' : 	url = 'dog.html';
	     	break;
case 'gerbil' : url = 'gerbil.html';
		break;
case 'gopher' : url = 'gopher.html';
		break;
}
// window.location.href = url;
alert('You would have been taken to the ' + favorite + ' page (' + url + '), but this is just a demo!');
}

Second is how to get the links to work, I want to use the

a href="'

link, but I dunno how to make it so it works with the javascript.
I do have this

onClick="SetCookie();">

but where to put it? how to edit and use it?