见代码：
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Object</title> 6 7 </head> 8 <body> 9 <script type="text/javascript"> 10 // let obj = {}; 11 // let arr = []; 12 var obj = {}; 13 var arr = []; 14 15 console.log(typeof obj);//object 16 console.log(typeof arr);//object 17 console.log(typeof null);//object 18 console.log(typeof ‘‘);//string 19 console.log(typeof undefined);//undefined 20 21 console.log(‘*******************************************‘); 22 23 console.log(typeof obj === ‘object‘);//true 24 console.log(typeof arr === ‘object‘);//true 25 console.log(typeof null === ‘object‘);//true 26 console.log(typeof ‘‘ === ‘object‘);//false 27 console.log(typeof undefined === ‘object‘);//false 28 29 console.log(‘*******************************************‘); 30 31 console.log("typeof obj === ‘object‘:" + typeof obj === ‘object‘);//false 32 console.log("typeof arr === ‘object‘:" + typeof arr === ‘object‘);//false 33 console.log("typeof null === ‘object‘:" + typeof null === ‘object‘);//false 34 console.log("typeof ‘‘ === ‘object‘:" + typeof ‘‘ === ‘object‘);//false 35 console.log("typeof undefined === ‘object‘:" + typeof undefined === ‘object‘);//false 36 37 console.log(‘------------------优先级搞的鬼‘); 38 39 console.log("typeof obj === ‘object‘:" + (typeof obj === ‘object‘));//typeof obj === ‘object‘:true 40 console.log("typeof arr === ‘object‘:" + (typeof arr === ‘object‘));//typeof arr === ‘object‘:true 41 console.log("typeof null === ‘object‘:" + (typeof null === ‘object‘));//typeof null === ‘object‘:true 42 console.log("typeof ‘‘ === ‘object‘:" + (typeof ‘‘ === ‘object‘));//typeof ‘‘ === ‘object‘:false 43 console.log("typeof undefined === ‘object‘:" + (typeof undefined === ‘object‘));//typeof undefined === ‘object‘:false 44 45 46 console.log(‘------------------优先级搞的鬼‘); 47 console.log(("typeof obj === ‘object‘:" + typeof obj) === ‘object‘);//false 48 console.log(("typeof arr === ‘object‘:" + typeof arr) === ‘object‘);//false 49 console.log(("typeof null === ‘object‘:" + typeof null) === ‘object‘);//false 50 console.log(("typeof ‘‘ === ‘object‘:" + typeof ‘‘) === ‘object‘);//false 51 console.log(("typeof undefined === ‘object‘:" + typeof undefined) === ‘object‘);//false 52 //"typeof obj === ‘object‘:object“ === ‘object‘ --------false 53 54 console.log(‘*******************************************‘); 55 56 console.log("Object.prototype.toString.call(obj) === ‘[object Object]‘:" + (Object.prototype.toString.call(obj)));//Object.prototype.toString.call(obj) === ‘[object Object]‘:[object Object] 57 console.log("Object.prototype.toString.call(arr) === ‘[object Object]‘:" + (Object.prototype.toString.call(arr)));//Object.prototype.toString.call(arr) === ‘[object Object]‘:[object Array] 58 console.log("Object.prototype.toString.call(null) === ‘[object Object]‘:" + (Object.prototype.toString.call(null)));//Object.prototype.toString.call(null) === ‘[object Object]‘:[object Null] 59 console.log("Object.prototype.toString.call(‘‘) === ‘[object Object]‘:" + (Object.prototype.toString.call(‘‘)));//Object.prototype.toString.call(‘‘) === ‘[object Object]‘:[object String] 60 console.log("Object.prototype.toString.call(undefined) === ‘[object Object]‘:" + (Object.prototype.toString.call(undefined)));// Object.prototype.toString.call(undefined) === ‘[object Object]‘:[object Undefined] 61 62 console.log(‘*******************************************‘); 63 //严谨的判断Object方式： 64 console.log("Object.prototype.toString.call(obj) === ‘[object Object]‘:" + (Object.prototype.toString.call(obj) === "[object Object]"));//Object.prototype.toString.call(obj) === ‘[object Object]‘:true 65 console.log("Object.prototype.toString.call(arr) === ‘[object Object]‘:" + (Object.prototype.toString.call(arr) === "[object Object]"));//Object.prototype.toString.call(arr) === ‘[object Object]‘:false 66 console.log("Object.prototype.toString.call(null) === ‘[object Object]‘:" + (Object.prototype.toString.call(null) === "[object Object]"));// Object.prototype.toString.call(null) === ‘[object Object]‘:false 67 console.log("Object.prototype.toString.call(‘‘) === ‘[object Object]‘:" + (Object.prototype.toString.call(‘‘) === "[object Object]"));// Object.prototype.toString.call(‘‘) === ‘[object Object]‘:false 68 console.log("Object.prototype.toString.call(undefined) === ‘[object Object]‘:" + (Object.prototype.toString.call(undefined) === "[object Object]"));//Object.prototype.toString.call(undefined) === ‘[object Object]‘:false 69 70 </script> 71 </body> 72 </html>
原文：http://www.cnblogs.com/allearner/p/5058735.html
