1.
<!DOCTYPE html>
<html>
<head>
<title>学生信息管理</title>
<style>
.student {
padding: 10px;
margin: 5px;
border: 1px solid #ccc;
}
.highlight {
background-color: #f0f0f0;
}
</style>
</head>
<body>
<div id="student-list">
<div class="student">张三</div>
<div class="student">李四</div>
<div class="student">王五</div>
<div class="student">赵六</div>
<div class="student">钱七</div>
</div>
<button id="add-label">添加优秀标签</button>
<button id="toggle-bg">切换背景</button>
<button id="add-number">添加序号</button>
<script>
var ostudents = document.getElementsByClassName("student");
var oaddLabel = document.getElementById("add-label");
var otoggleBg = document.getElementById("toggle-bg");
var oaddNumber = document.getElementById("add-number");
oaddLabel.onclick = function () {
for (var i = 0; i < ostudents.length; i++) {
ostudents[i].textContent += "-优秀学生";
}
};
otoggleBg.onclick = function () {
for (var i = 0; i < ostudents.length; i++) {
ostudents[i].classList.toggle("highlight");
}
};
oaddNumber.onclick = function () {
for (var i = 0; i < ostudents.length; i++) {
ostudents[i].textContent = (i + 1) + "." + ostudents[i].textContent;
}
};
</script>
</body>
</html>
2.
<!DOCTYPE html>
<html>
<head>
<title>简易任务管理器</title>
<style>
.task {
padding: 8px;
margin: 5px;
border: 1px solid #ddd;
}
.task:hover {
background-color: #e6f7ff;
}
/* 浅蓝色背景 */
.completed::before {
content: "✅ ";
}
/* 完成符号 */
.delete-btn {
margin-left: 10px;
color: red;
cursor: pointer;
}
.delete-btn:hover {
text-decoration: underline;
}
</style>
</head>
<body>
<h3>我的任务列表</h3>
<input type="text" id="task-input" placeholder="输入新任务">
<button id="add-task">添加任务</button>
<br><br>
<button id="mark-all">标记全部完成</button>
<button id="clear-completed">清除完成项</button>
<div id="task-list">
<!-- 任务将动态添加到这里 -->
</div>
<script>
var otaskInput = document.getElementById("task-input");
var oaddTask = document.getElementById("add-task");
var omarkAll = document.getElementById("mark-all");
var oclearCompleted = document.getElementById("clear-completed");
var otaskList = document.getElementById("task-list");
//添加任务
oaddTask.onclick = function () {
var taskText = otaskInput.value;
//创建任务元素
var taskElement = document.createElement("div");
taskElement.className = "task";
//创建任务文本节点
var taskContent = document.createTextNode(taskText);
//创建删除按钮
var delBtn = document.createElement("span");
delBtn.className = "delete-btn";
delBtn.textContent = "删除";
delBtn.onclick = function () {
taskElement.remove();
};
//组装任务并添加至任务列表
taskElement.appendChild(taskContent);
taskElement.appendChild(delBtn);
otaskList.appendChild(taskElement);
//清空输入框
otaskInput.value = '';
};
//标记全部完成
omarkAll.onclick=function(){
var allTask=document.getElementsByClassName("task");
for(var i=0;i<allTask.length;i++){
allTask[i].classList.add("completed");
}
};
//清空完成
oclearCompleted.onclick=function(){
var completedTasks=document.querySelectorAll(".task.completed");
for(var i=0;i<completedTasks.length;i++){
completedTasks[i].remove();
}
}
</script>
</body>
</html>
3.
<!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>JS-事件-案例</title>
</head>
<body>
<!-- 灯泡图片及控制按钮 -->
<img id="light" src="img/off.gif"> <br>
<input type="button" value="点亮">
<input type="button" value="熄灭">
<br> <br>
<!-- 文本添加区域 -->
<input type="text" id="name" placeholder="请输入">
<input type="button" id="add" value="添加">
<input type="button" id="good" value="好棒棒">
<div id="texe-list"></div>
<br> <br>
<!-- 复选框及控制按钮 -->
<input type="checkbox" name="hobby"> 电影
<input type="checkbox" name="hobby"> 旅游
<input type="checkbox" name="hobby"> 游戏
<br>
<input type="button" value="全选">
<input type="button" value="反选">
<script>
// 获取DOM元素
var img = document.getElementById("light");
var allBtn = document.getElementsByTagName("input"); // 所有input元素集合
// 文本添加相关元素
var oaddText = document.getElementById("name");
var oaddBtn = document.getElementById("add");
var otextList = document.getElementById("texe-list");
var ogoodBtn = document.getElementById("good");
// 复选框相关元素
var ohobby = document.getElementsByName("hobby");
// 1. 灯泡控制功能
var lightBtn = allBtn[0]; // 点亮按钮(第1个input)
var offBtn = allBtn[1]; // 熄灭按钮(第2个input)
lightBtn.onclick = function () {
img.src = "img/on.gif"; // 切换为点亮图片
};
offBtn.onclick = function () {
img.src = "img/off.gif"; // 切换为熄灭图片
};
// 2. 列表添加功能
oaddBtn.onclick = function () {
var addText = oaddText.value;
var addElement = document.createElement("div");
addElement.className = "text";
var addContont = document.createTextNode(addText);
addElement.appendChild(addContont);
otextList.appendChild(addElement);
oaddText.value = ""; // 清空输入框
};
// 3. 给列表项添加"very good"
ogoodBtn.onclick = function () {
var otext = document.getElementsByClassName("text");
for (var i = 0; i < otext.length; i++) {
// 每个列表项创建独立的红色文字元素
var goodSpan = document.createElement("span");
goodSpan.style.color = "red";
goodSpan.textContent = " very good";
otext[i].appendChild(goodSpan);
}
};
// 4. 复选框全选/反选功能
var markAllBtn = allBtn[8]; // 全选按钮(第9个input)
var clearAllBtn = allBtn[9]; // 反选按钮(第10个input)
// 全选功能
markAllBtn.onclick = function () {
for (var i = 0; i < ohobby.length; i++) {
ohobby[i].checked = true;
}
};
// 反选功能(原代码变量名clearAllBtn实际为反选,保持原有逻辑)
clearAllBtn.onclick = function () {
for (var i = 0; i < ohobby.length; i++) {
ohobby[i].checked = false;
}
};
</script>
</body>
</html>

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