//1 判断是否为数组类型var a=[0];console.log(isArray(a));function isArray(obj){return (typeof obj=='object') && obj.constructor==Array;}console.log("2-----------------------------------")//2 判断是否为字符串类型console.log(isString('test'));console.log(isString(10));function isString(str){return (typeof str=='string')&&str.constructor==String;}console.log("3-----------------------------------")//3 判断是否为数值类型console.log(isNumber('test'));console.log(isNumber(10));function isNumber(obj){return (typeof obj=='number')&&obj.constructor==Number;}console.log("4-----------------------------------")//4 判断是否为日期类型console.log(isDate(new Date()));console.log(isDate(10));function isDate(obj){return (typeof obj=='object')&&obj.constructor==Date;}console.log("5-----------------------------------")//5 判断是否为函数console.log(isFunction(function test(){}));console.log(isFunction(10));function isFunction(obj){return (typeof obj=='function')&&obj.constructor==Function;}console.log("6-----------------------------------")//6 判断是否为对象console.log(isObject(new Object()));console.log(isObject(10));function isObject(obj){return (typeof obj=='object')&&obj.constructor==Object;}/** null 数组  日期 对象返回的是object类型*/

// js数据类型： number   string    boolean   undefined   object和函数类型 function
console.log(typeof null)//objectconsole.log(typeof Function)//function  Function是包装类型console.log(typeof undefined)//undefinedvar message;console.log(message)//undefined 定义了没有赋值console.log(typeof message)//undefined 类型console.log(null == undefined)//true/** true==1;fase==0;* */console.log(true == 1)//trueconsole.log(false == 0)//trueconsole.log(false ==2)//falsevar str="";console.log(str==0);//true;空字符串将会把值转换为0console.log(typeof str)//string

　　var str2=new String('A');　　console.log(str2) //String { 0="A"}

    var gettype=Object.prototype.toStringgettype.call('aaaa')             //[object String]gettype.call(2222)              //[object Number]gettype.call(true)              //[object Boolean]gettype.call(undefined)         //[object Undefined]gettype.call(null)              //[object Null]gettype.call({})                //[object Object]gettype.call([])                //[object Array]gettype.call(function(){})      //[object Function]

/*    其实js 里面还有好多类型判断[object HTMLDivElement]   div 对象  ,[object HTMLBodyElement]  body 对象,[object Document](IE)或者  [object HTMLDocument]（firefox,google） ......各种dom节点的判断，这些东西在我们写插件的时候都会用到。*/var   gettype=Object.prototype.toStringvar    utility={isObj:function(o){return    gettype.call(o)=="[object Object]";},isArray:function(o){return    gettype.call(o)=="[object Array]";},isNULL:function(o){return    gettype.call(o)=="[object Null]";},isDocument:function(){return    gettype.call(o)=="[object Document]"|| [object HTMLDocument];}//...}