Detecting support of local storage

function LocalStorage(){}

extend(LocalStorage.prototype, {
    isSupportCookie : function(){
        return navigator.cookieEnabled;
    },
    isSupportUserData : function(){
        var t = document.createElement('input');
        return (typeof t.addBehavior !== 'undefined');
    },
    isSupportDOMStorage : function(){
        return (typeof window.localStorage !== 'undefined');
    }
});