js中的typeof和instanceof和===

 ???//五种基本类型 ???var num=1; ???var str="abc"; ???var bl=true; ???var nu=null; ???var undef=undefined; ???//三种特殊类型 ???var obj=new Object(); ???var arr2=["1",2,true]; ???var fun=function () { ???????????} ???write("-------typeof-----------") ???write(num,typeof num);//1 number ???write(str,typeof str);//abc string ???write(bl,typeof bl);//true boolean ???write(nu,typeof nu);//null object ???write(undef,typeof undef)//undefined undefined ???write(obj,typeof obj);//[object Object] object ???write(arr2,typeof arr2);//1,2,true object ???write("-----------===-----------") ???write(num,typeof num==="number");//1 true ???write(str,typeof str==="string");//abc true ???write(bl,typeof bl==="boolean");//true true ???write(nu,typeof nu==="object");//null true ???write(undef,typeof undef==="undefined")//undefined true ???write(obj,typeof obj==="object");//[object Object] true ???write(arr2,typeof arr2==="object");//1,2,true true ???write(fun,typeof fun==="function");//function () { } true ???write("---------instanceof---------------") ???write(obj,obj instanceof Object)//[object Object] true ???write(arr2,arr2 instanceof Array);//1,2,true true ???write(arr2,arr2 instanceof Object);//1,2,true true ???write(fun, fun instanceof Function)//function () { } true ???write(fun, fun instanceof Object)//function () { } true