JS函数案例

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秒转化成小时案例

<!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>
        /*
            小时:  h = parseInt(总秒数 / 60 / 60 % 24)
            分钟:  m = parseInt(总秒数 / 60 % 60 )
            秒数:  s = parseInt(总秒数 % 60)
        */

        // 用户输入的秒数 转换为时分秒 不足两位补0
        let times = +prompt('请您输入秒数')


        function getTime(time) {
            let h = parseInt(time / 60 / 60 % 24)
            let m = parseInt(time / 60 % 60)
            let s = parseInt(time % 60)

            // 补0的操作  ctrl+d 快速选中相同的内容
            h = h < 10 ? '0' + h : String(h)
            m = m < 10 ? '0' + m : String(m)
            s = s < 10 ? '0' + s : String(s)
            // s = s < 10 ? '0' + s : s.toString()

            // 不做任何处理 直接返回三个值
            return [h, m, s]
        }

        let res = getTime(times)
        console.log(res);
        document.write(`您输入的秒数为${time},转换的时间为:${res[0]}:${res[1]}:${res[2]}`)
    </script>
</body>

</html>

求数组的最大值和最小值

<!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>
        // 封装一个 求数组的最大值和最小值的函数

        function getMaxMin(arr) {
            let max = min = arr[0]
            for (let i = 0; i < arr.length; i++) {
                max = arr[i] > max ? arr[i] : max
                min = arr[i] < min ? arr[i] : min
            }
            return [max, min]
        }

        let res = getMaxMin([33, 12, 456, 0, -10])
        let res2 = getMaxMin([21321, 21321, -456, 0, -10])
        document.write(`最大值为${res[0]},最小值为${res[1]}`)
        document.write(`最大值为${res2[0]},最小值为${res2[1]}`)
    </script>
</body>

</html>

求两个数的最大值

<!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>
        // 封装一个 求两个数的最大值的函数  (函数的实参让用户输入)

        function getMax(a, b) {
            return a > b ? a : b
        }

        let num1 = +prompt('输入数字1')
        let num2 = +prompt('输入数字2')

        // 实参是允许传递变量

        let res = getMax(num1, num2)
        document.write(`您输入的数字中 较大的值为${res}`)


    </script>
</body>

</html>

return返回多个值

<!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>
        // 封装一个计算两个数字的和和差的函数
        function getRes(a, b) {
            let he = a + b
            let cha = a - b
            return [he, cha]
        }

        let res = getRes(3, 1)
        document.write(`和为${res[0]},差为${res[1]}`)
    </script>
</body>

</html>