var test = (function(){    var self = {};    self.alert = function(){                console.log('this is alert')    }    //sleep    self.sleep = function(){},    self.extendJson = function(){},    self.formatParams = function(){},    self.httpAgent = function(){},    self.randomChar = function(){},    self.getCharLen = function(){},    self.subStr = function(){},    self.getPara = function(){},    self.subTime = function(){},//计算时间差，返回毫秒数    self.getUnixTime = function(){},//获取unix时间    self.formatTime = function(){},//时间格式化    self.getCookie = function(){},//获取cookie    self.setCookie = function(){},//设置cookis    self.getMeta = function(key){
   //获取meta标签内容        return document.querySelector('meta[name="'+key+']').getAttribute('content');    },    self.setMeta = function(key,des){
   //设置meta内容        document.querySelector('meta[name="'+key+']').setAttribute('content','des');    },    self.setMetaKey = function(des){        document.querySelector('meta[name="keywords"]').setAttribute('content',des.replace(/"/g,'”'));    },    self.setMetaDes = function(des){        document.querySelector('meta[name="description"]').setAttribute('content',des.replace(/"/g,'”'));    },    self.setSeo = function(title,keywords,des){        document.title = title+'-'+document.title;        self.setMetaKey(keywords);        self.setMetaDes(des);    }    return self;}())