var a = [1, 2, 3];
var b = [1, 2, 3];

console.log(a.toString() === b.toString());  //true

但數組是復合數組就不行了
var a = [1, 2, {name: "zhang"}];
var b = [1, 2, {name: "zhangss"}];

console.log(a.toString() === b.toString());  //true (判斷失敗)

var a = [1, 2, 3];
var b = [1, 2, 3];

console.log(JSON.stringify(a) === JSON.stringify(b));  //true

復合數組也可以判斷
var a = [1, 2, {name: "zhang"}];
var b = [1, 2, {name: "zhangss"}];

console.log(JSON.stringify(a) === JSON.stringify(b));  //false

但數組位置變化無法判斷
var a = [2, 1, 3];
var b = [1, 2, 3];

console.log(JSON.stringify(a) === JSON.stringify(b));  //false (數組應該是相同的)

解決辦法很簡單，使用數組的sort()就行
var a = [2, 1, 3];
var b = [1, 2, 3];

console.log(JSON.stringify(a.sort()) === JSON.stringify(b.sort())); // true