Here is an implementation of a delete cookie function with unicode support from Mozilla:
function removeItem(sKey, sPath, sDomain) {
document.cookie = encodeURIComponent(sKey) +
"=; expires=Thu, 01 Jan 1970 00:00:00 GMT" +
(sDomain ? "; domain=" + sDomain : "") +
(sPath ? "; path=" + sPath : "");
}
removeItem("cookieName");
If you use AngularJs, try $cookies.remove (underneath it uses a similar approach):
$cookies.remove('cookieName');