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for循环与webAPI练习题

news 2025/8/20 2:40:31

爱太容易了，让爱维持才是最困难的部分

文章目录

- - - - for循环练习题
      - webAPI练习题

for循环练习题

练习1：计算1-100的和

 let sum = 0for (let i = 1; i <= 100; i++) {sum += i}console.log(sum)

练习2：将1-100之间所有是6的倍数的数字输出到控制台

for (let i = 1; i <= 100; i++) {if (i % 6 === 0) {console.log(i)}
}

练习3：在页面中打印两行每行中有10颗☆

for (let i = 1; i <= 2; i++) {document.write('<br/>')for (let j = 1; j <= 10; j++) {document.write('☆')}
}

练习4：在页面中打印直角三角形

for (let i = 1; i <= 10; i++) {document.write('<br />')for (let j = 1; j <= i; j++) {document.write('♡')}
}

练习5：九九乘法表

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><style>td {border: 1px solid red;width: 80px;text-align: center;}tr:nth-child(odd) {background-color: pink;}tr:nth-child(even) {background-color: orange;}</style>
</head><body><script>document.write('<table>')for (let i = 1; i <= 9; i++) {document.write('<tr>')for (let j = 1; j <= i; j++) {document.write(`<td>${j} x ${i} = ${j * i}</td>`)}document.write('</tr>')}document.write('</table>')</script>
</body></html>

webAPI练习题

练习1：图片切换

<!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><style>.main {width: 600px;margin: 20px auto;}.first button {margin: 0 50px;}.second img {display: block;width: 315px;height: 300px;margin: 20px 0;}</style>
</head><body><div class="main"><div class="first"><button id="prev">上一张</button><button id="next">下一张</button></div><div class="second"><img src="img/1.jpg" id="img"></div><div class="three"><div id="info"></div></div></div><script>var prev = document.getElementById('prev')var next = document.getElementById('next')var img = document.getElementById('img')var info = document.getElementById('info')var index = 0var imgArr = ['img/1.jpg', 'img/2.jpg', 'img/3.jpg', 'img/4.jpg', 'img/5.jpg', 'img/6.jpg']info.innerHTML = `第${imgArr.length-5}张 / 共${imgArr.length}张`prev.onclick = function () {index--if (index < 0) {index = imgArr.length - 1}img.src = imgArr[index]info.innerHTML = `第${index+1}张 / 共${imgArr.length}张`}next.onclick = function () {index++if (index > imgArr.length - 1) {index = 0}img.src = imgArr[index]info.innerHTML = `第${index+1}张 / 共${imgArr.length}张`}</script>
</body></html>

练习2：倒计时

<!DOCTYPE html>
<html lang="zh-CN"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><style>.form {width: 600px;margin: 100px auto;}.row {width: 100%;display: flex;border-top: 1px solid #0094ff;border-bottom: 1px solid #0094ff;}.cols-1 {flex: 1;}.cols-2 {flex: 2;}.cell {border-left: 1px solid #0094ff;padding: 10px 3px;line-height: 42px;text-align: center;}.cell:last-child {border-right: 1px solid #0094ff;}.text {width: 268px;height: 30px;padding: 4px;}.btn {height: 38px;width: 200px;}</style>
</head><body><div class="form"><div class="row"><div class="cell cols-1">请输入手机号</div><div class="cell cols-2"><input type="text" class="text"></div><div class="cell cols-1"><input type="button" value="获取验证码" id="getCode" class="btn"></div></div></div></body><script>var btn = document.getElementById('getCode')btn.onclick = function () {// 禁用按钮btn.disabled = true// 定义数字var i = 5// 修改按钮内容btn.value = '验证码已发送' + i// 定时器var str = window.setInterval(function () {i--// 设置按钮内容btn.value = '验证码已发送' + iif (i === 0) {// 清除定时器window.clearInterval(str)// 修改按钮内容btn.value = '获取验证码'// 启用按钮btn.disabled = false}}, 1000)}
</script></html>

练习3：事件流

<!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>事件冒泡</title>
</head><body><div><p id="parEle">我是父元素<span id="sonEle">我是子元素</span></p></div><script>var parEle = document.getElementById('parEle')var sonEle = document.getElementById('sonEle')parEle.addEventListener('click', function () {console.log('父元素冒泡')}, false)parEle.addEventListener('click', function () {console.log('父元素捕获')}, true)sonEle.addEventListener('click', function () {console.log('子元素冒泡')}, false)sonEle.addEventListener('click', function () {console.log('子元素捕获')}, true)</script>
</body></html>