76、数学内置对象Math

2024-10-04 / 0 评论 / 5 阅读 / 正在检测是否收录...

10/04

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 属性
        console.log(Math.PI)
        //方法
        // ceil 天花板 向上取整
        console.log(Math.ceil(1.1)) //2
        console.log(Math.ceil(1.5)) //2
        // floor 地板 向下取整
        console.log(Math.floor(1.1))//1
        console.log(Math.floor(1.1))//1
        console.log(Math.floor(1.9))//1
        // 四舍五入 round
        console.log(Math.round(1.1))//1
        console.log(Math.round(1.5))// 2
        console.log(Math.round(-1.5))// -1
        console.log(Math.round(-1.51))// -2

        //取整函数 parseInt(1.2) //1
        //取整函数 parseInt('12px') //12

        console.log(Math.max(1,2,3,4,5)) //最大值 5
        console.log(Math.min(1,2,3,4,5)) // 最小值 1
        console.log(Math.abs(-1)) //1

        //null 类似 let obj = {}
        let obj = null // 空对象
    </script>
</body>
</html>

JavaScript