如何从JavaScript中的数组中选择一个随机元素（） _前端开发

任务是使用JavaScript从数组中选择随机元素。
方法1：

采用Math.random()函数获取介于(0-1, 1除外)之间的随机数。
将其乘以数组长度即可得到介于(0-arrayLength)之间的数字。
采用Math.floor()获取从(0到arrayLength-1)的索引。

例子：本示例实现了上述方法。

< !DOCTYPE HTML> < html > < head > < title > How to select a random element from array in JavaScript ? < / title > < / head > < body style = "text-align:center; " > < h1 style = "color:green; " > lsbin < / h1 > < p id = "GFG_UP" style = "font-size: 15px; font-weight: bold; " > < / p > < button id = "button" onclick = "GFG_Fun()" > click here < / button > < p id = "GFG_DOWN" style = "font-size: 24px; font-weight: bold; color: green; " > < / p > < script > var up = document.getElementById('GFG_UP'); var down = document.getElementById('GFG_DOWN'); var arr = ["GFG_1", "lsbin", "Geeks", "Computer Science Portal"]; up.innerHTML = "Click on the button to check " + "the type of element.< br > < br > " + arr; function GFG_Fun() { down.innerHTML = arr[Math.floor(Math.random() * arr.length)]; } < / script > < / body > < / html >

输出如下：
在单击按钮之前：

文章图片
单击按钮后：

文章图片
方法二：

的随机(a, b)方法用于生成介于(a至b, b除外)之间的数字。
取下限范围为从(1到arrayLength)的数字。
减去1得到的索引范围是(0到arrayLength-1)。

例子：本示例实现了上述方法。

< !DOCTYPE HTML> < html > < head > < title > How to select a random element from array in JavaScript ? < / title > < / head > < body style = "text-align:center; " > < h1 style = "color:green; " > lsbin < / h1 > < p id = "GFG_UP" style = "font-size: 15px; font-weight: bold; " > < / p > < button id = "button" onclick = "GFG_Fun()" > click here < / button > < p id = "GFG_DOWN" style = "font-size: 24px; font-weight: bold; color: green; " > < / p > < script > var up = document.getElementById('GFG_UP'); var down = document.getElementById('GFG_DOWN'); var arr = ["GFG_1", "lsbin", "Geeks", "Computer Science Portal"]; up.innerHTML = "Click on the button to select" + " random element from the" + " array.< br > < br > " + arr; function random(mn, mx) { return Math.random() * (mx - mn) + mn; } function GFG_Fun() { down.innerHTML = arr[Math.floor(random(1, 5))-1]; } < / script > < / body > < / html >

输出如下：
在单击按钮之前：