refactoring of w3schools cookie functions ( http://www.w3schools.com/js/js_cookies.asp )

new-cookies.js

function cookieValueFor(cookieName)
{
    var cookies = document.cookie.split(";");

    for (var i = 0; i < cookies.length; i++)
    {
        var currentCookie = cookies[i];
        var currentCookieName = currentCookie.substr(0 , currentCookie.indexOf("=")).replace(/^\s+|\s+$/g,"");

        if (currentCookieName == cookieName)
        {
            var currentCookieValue = currentCookie.substr(currentCookie.indexOf("=") + 1);
            return unescape(currentCookieValue);
        }
    }
}

function setCookie(cookieName, cookieValue, daysUntilExpiration)
{
    var expirationString = "";

    if (daysUntilExpiration != null)
    {
        var expirationDate = new Date();
        expirationDate.setDate(expirationDate.getDate() + daysUntilExpiration);
        expirationString = "; expires=" + expirationDate.toUTCString();
    }

    document.cookie = cookieName + "=" + escape(cookieValue) + expirationString;
}

old-cookies.js

function getCookie(c_name)
{
var i,x,y,ARRcookies=document.cookie.split(";");
for (i=0;i<ARRcookies.length;i++)
{
  x=ARRcookies[i].substr(0,ARRcookies[i].indexOf("="));
  y=ARRcookies[i].substr(ARRcookies[i].indexOf("=")+1);
  x=x.replace(/^\s+|\s+$/g,"");
  if (x==c_name)
    {
    return unescape(y);
    }
  }
}

function setCookie(c_name,value,exdays)
{
var exdate=new Date();
exdate.setDate(exdate.getDate() + exdays);
var c_value=escape(value) + ((exdays==null) ? "" : "; expires="+exdate.toUTCString());
document.cookie=c_name + "=" + c_value;
}