(function(){    var days = ['Sun','Mon','Tue','Wed','Thu','Fri','Sat']    var today = new Date()    var msg = "Today is" + days[today.getDay()] + ',' + today.getDate()    console.log(msg)})();   // Today isThu,29// 即时函数的参数(function(who,when){    console.log(' i met ' + who + ' on ' + when)})("cynthai",new Date());  //i met cynthai on Thu Oct 29 2015 18:03:09 GMT+0800 (中国标准时间)