javascript 判斷各個對象類型

判斷對象有兩種格式
1.if(typeof obj == "string"){}
2.if(obj.constructor == "String"){}

                     判斷對象類型表
 變量             typeof判斷          constructor判斷
{an;"obj"}         object                 Object
["an","ary"]       array                  Array
function(){}       function               Function
"a string"         string                 String
555555             number                 Number
true               boolean                Boolean
new User()         object                 User