Here’s some (slightly simplified) code taken from Thau’s Advanced JavaScript Tutorial that allows you to isolate a specific cookie.

function WM_readCookie(name) {

if (document.cookie == '') {

// there's no cookie, so go no further

	return false;

	} else {

// there is a cookie

	var firstChar, lastChar;

	var theBigCookie = document.cookie;

	firstChar = theBigCookie.indexOf(name);

// find the start of 'name'

	if(firstChar != -1) {

// if you found the cookie

	firstChar += name.length + 1;

// skip 'name' and '='

	lastChar = theBigCookie.indexOf(';', firstChar);

// Find the end of the value string (i.e. the next ';').

	if(lastChar == -1) lastChar = theBigCookie.length;

	return unescape(theBigCookie.substring(firstChar, lastChar));

	} else {

// If there was no cookie of that name, return false.

	return false;

	}

	}

	}

// WM_readCookie