javascript 基本类型

undefined, null, bool, number, string, object 和 function

Number, String, Object, Function 等是 JavaScript 的内置函数

typeof

返回值只有 undefined string number boolean object function

typeof 12312.23  //"number"
typeof "nihao"  //"string"
typeof undefined  //"undefined"
typeof true  //"boolean"
typeof null  //"object"
typeof setInterval   //"function"

instanceof

var s = new Number(234);
s instanceof Number; //true

Object.prototy.call()

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