1.最大数为2^53，+1仍是2^53javascript
2.String('A')==='A';new String('A')!=='A'java
3.小数进行运算有精度通常不能这么用小数比较，能够扩大精度至整数数组
4.typeof null 为"object",null instanceof Object 为falseapp
5.数组.filter时undefined不会触发prototype
6.-9 % 2 = -1；后台语言会返回1code
7.parseInt(A,B) ;A为B进制的数，B为进制，结果返回10进制的数，B不合法就默认为10或者NaN。ip
8.Array.isArray( Array.prototype ) = trueelement
9.var a = [0]; if (a) {console.log(a == true);}get
10. map is only invoked for elements of the Array which have been initialized.it
11. in javascript variables are tied to the arguments object so changing the variables changes arguments and changing arguments changes the local variables even when they are not in the same scope.
12.var a = 111111111111111110000, b = 1111; a + b;
13.https://javascript-puzzlers.herokuapp.com/
14.Number.MIN_VALUE == 5e-324
15.2 == [[[2]]]
16.3..toString() = "3"
17.name is a read only property
18.Date(0) 当前时间，new Date(0)；1970
19.var min = Math.min(), max = Math.max() min > max Infinity > -Infinity