Math对象

1.取绝对值 //100

var value = Math.abs(-100);
console.log(value);

2.向上取整 //2

var value = Math.ceil(1.2);
console.log(value);

3.向下取整 // 1

var value = Math.floor(1.8);
console.log(value);

4.最大值 // 67

var value = Math.max(23,34,5,67,8);
console.log(value);

5.最小值//5

var value = Math.min(23,34,5,67,8);
console.log(value);

. 四舍五入//1

var value = Math.round(1.3);
console.log(value);

7，随机数
0-1包括0
但不包括1

var value = Math,random();
console.log(value);