js cookie 工具

var CookieUtil = {
    get: function(name) {
        var cookieName = encodeURIComponent(name) + "=",
            cookieStart = document.cookie.indexOf(cookieName),
            cookieValue = null;
        
        if (cookieStart > -1) {
            var cookieEnd = document.cookie.indexOf(";", cookieStart);
            if (cookieEnd == -1)  {
                cookieEnd = document.cookie.length;
            }
            cookieValue = decodeURIComponent(document.cookie.substring(cookieStart + cookieName.length, cookieEnd));
            
        }
        return cookieValue;
    },
    set: function(name, value, expires, path, domain, secure)  {
        var  cookieText = encodeURIComponent(name) + "=" + encodeURIComponent(value);
        
        if (expires instanceof Date)  {
            cookieText += "; expires=" + expires.toDateString();  //toGMTString
        }
        
        if (path)  {
            cookieText += "; path=" + path;
        }
        
        if (domain)  {
            cookieText += "; domain=" + domain;
        }
        
        if (secure)  {
            cookieText += "; secure";
        }
        
        document.cookie = cookieText;
    },
    unset: function(name, path, domain, secure)  {
        this.set(name, "", new Date(0), path, domain, secure);
    }   
};

子cookie

//name=name1=value&name2=value&name3=value&name4=value
//子cookie 的处理方法
var SubCookieUtil =  {
    get: function (name, subName)  {
        var subCookies = this.getAll(name);
        return subCookies ? subCookies[subName]: null;
    },
    
    getAll: function (name)  {
        var cookieName = encodeURIComponent(name) + "=", 
            cookieStart = document.cookie.indexOf(cookieName),
            cookieValue = null,
            result = {};
        
        if (cookieStart > -1)  {
            var cookieEnd = document.cookie.indexOf(';', cookieStart);
            if (cookieEnd == -1) {
                cookieEnd = document.cookie.length;
            }
            
            cookieValue = document.cookie.substring(cookieStart + cookieName.length, cookieEnd);
            
            if (cookieValue.length > 0)  {
                var subCookies = cookieValue.split(' & ');
                
                for (var i =0, len = subCookies.length; i < len; i++) {
                    var parts = subCookies[i].split('=');
                    result[decodeURIComponent(parts[0])] = decodeURIComponent(parts[1]);
                }
                return result;
            }
            
            return null;
        }
    },
    
    set: function (name, subName, value, expires, path, domain, secure) {
        var subcookies = this.getAll(name) || {};
        subcookies[subName] = value;
        this.setAll(name, subcookies, expires, path, domain, secure);
    },
    setAll: function (name, subcookies, expires, path, domain, secure) {
        var cookieText = encodeURIComponent(name) + '=';
        var subCookieParts = new Array();
        
        for (var subName in subcookies)  {
            if (subName.length > 0 && subcookies.hasOwnProperty(subName))  {
                subCookieParts.push(encodeURIComponent(subName) + '=' + encodeURIComponent(subcookies[subName]));
            }
        }
        
        if (subCookieParts.length > 0)  {
            cookieText += subCookieParts.join(" & ");
            
            if (expires instanceof Date)  {
                cookieText += '; expires=' + expires.toDateString();
            }
            
            if (path)  {
                cookieText += '; path=' + path;
            }
            
            if (domain)  {
                cookieText += '; domain' + domain;
            }
            
            if (secure) {
                cookieText += '; secure';
            }
        } else {
            cookieText += '; expires=' + (new Date(0).toDateString());
        }
        
        document.cookie = cookieText;
    },
    
    unset: function (name, subName, path, domain, secure) {
        var subcookies = this.getAll(name);
        if (subcookies) {
            delete subcookies[subName];
            this.setAll(name, subcookies, null, path, domain, secure);
        }
    },
    unsetAll: function (name, path, domain, secure) {
        this.setAll(name, null, new Date(0), path, domain, secure);
    }
};

来自：《JavaScript 高级程序设计第二版》