习题是提升的根本,可以将自己的知识更好地巩固
第一天的课程总共有11道练习题,我们一一填写
1.点击按钮,切换图片
2. 点击按钮,修改图片的宽高 -- width、height属性
3. 点击按钮,修改div的样式 -- 预定义类名
4. 点击按钮,div进行显示和隐藏(两个按钮) -- 预定义类名
5. 点击按钮,div进行显示和隐藏(一个按钮) -- 预定义类名 + innerText属性
6. 点击按钮,循环切换图片 -- src属性
7.点击按钮修改p标签的内容 -- innerText属性
8点击按钮,同时修改多个p标签的内容
9. 给多个按钮注册点击事件
10. 隔行变色
11. 给多个按钮注册点击事件,点击的那个变成红色
1.点击按钮,切换图片
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button id="but">点击切换图片</button>
<img id="tu" src="imgs/1.jpg" alt="图片1" title="这是图片1">
<script>
// 点击按钮,切换图片
var but = document.getElementById("but");
var tu = document.getElementById("tu");
but.onclick = function(){
tu.src = "imgs/2.jpg";
tu.title = "这是图片2";
}
</script>
</body>
</html>
2. 点击按钮,修改图片的宽高 -- width、height属性
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button id="but">点击切换图片宽高</button>
<br>
<img id="tu" width="400" height="500" src="imgs/1.jpg" alt="图片1" title="这是图片1">
<script>
//1. 点击按钮,修改图片的宽高 -- width、height属性
var but = document.getElementById("but");
var tu = document.getElementById("tu");
but.onclick = function(){
tu.width = "200";
tu.height = "250";
}
</script>
</body>
</html>
3. 点击按钮,修改div的样式 -- 预定义类名
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
div{
width: 200px;
height: 200px;
background-color: pink;
}
.d{
width: 100px;
height: 100px;;background-color: red;
}
</style>
</head>
<body>
<button id="but">按钮</button>
<div id="d">我是一个盒子</div>
<script>
//2. 点击按钮,修改div的样式 -- 预定义类名
var but = document.getElementById("but");
var d = document.getElementById('d');
but.onclick = function(){
d.className = "d";
}
</script>
</body>
</html>
4. 点击按钮,div进行显示和隐藏(两个按钮) -- 预定义类名
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.xian{
width: 100px;
height: 100px;
background-color: pink;
}
.yin{
display: block;
}
</style>
</head>
<body>
<button id="but1">显示</button>
<button id="but2">隐藏</button>
<div id="d"></div>
<script>
//3. 点击按钮,div进行显示和隐藏(两个按钮) -- 预定义类名
var but1 = document.getElementById("but1");
var but2 = document.getElementById("but2");
var d = document.getElementById("d");
but1.onclick = function(){
d.className = "xian";
}
but2.onclick = function(){
d.className = "yin";
}
</script>
</body>
</html>
5. 点击按钮,div进行显示和隐藏(一个按钮) -- 预定义类名 + innerText属性
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
div{
width: 200px;
height: 200px;
background-color: pink;
display: none;
}
.show{
display: block;
}
</style>
</head>
<body>
<button id="but">显示</button>
<div id="d"></div>
<script>
//4. 点击按钮,div进行显示和隐藏(一个按钮) -- 预定义类名 + innerText属性
var but = document.getElementById("but");
var d = document.getElementById("d");
but.onclick = function(){
if(but.innerText == "显示"){
d.className = "show";
but.innerText = "隐藏";
}else{
d.className = "";
but.innerText = " 显示 ";
}
}
</script>
</body>
</html>
6. 点击按钮,循环切换图片 -- src属性
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button id="but">切换</button>
<br>
<img id="tu" src="imgs/1.jpg" alt="">
<script>
var but = document.getElementById("but");
var tu = document.getElementById("tu");
var i = 0;
var arr = ["imgs/1.jpg",'imgs/01.jpg',"imgs/2.jpg","imgs/02.jpg"];
but.onclick = function(){
i++;
if(i == 4){
i = 0;
}
tu.src = arr[i];
}
</script>
</body>
</html>
7.点击按钮修改p标签的内容 -- innerText属性
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button id="but">点击更换</button>
<p id="prc">我是P标签</p>
<script>
// 1. 点击按钮修改p标签的内容 -- innerText属性
var but = document.getElementById("but");
var prc = document.getElementById("prc");
but.onclick = function(){
prc.innerText = "更改后的P";
}
</script>
</body>
</html>
8点击按钮,同时修改多个p标签的内容
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button id="but">更改</button>
<p>我是p标签</p>
<p>我是p标签</p>
<p>我是p标签</p>
<p>我是p标签</p>
<p>我是p标签</p>
<p>我是p标签</p>
<script>
//1. 点击按钮,同时修改多个p标签的内容
var but = document.getElementById("but");
// 这是数组
var ps = document.getElementsByTagName("p");
but.onclick = function(){
for(var i = 0 ; i < ps.length ;i++){
ps[i].innerText = "更改";
}
}
</script>
</body>
</html>
9. 给多个按钮注册点击事件
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<script>
//2. 给多个按钮注册点击事件
var buts = document.getElementsByTagName("button");
for(var i= 0; i < buts.length;i++){
buts[i].onclick = function(){
alert("哈哈");
}
}
</script>
</body>
</html>
10. 隔行变色
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.red{
background-color: red;
}
.green{
background-color: green;
}
</style>
</head>
<body>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<p>我是P标签</p>
<script>
//3. 隔行变色
var ps = document.getElementsByTagName("p");
for(var i = 0 ; i <ps.length ;i++){
if(i%2==0){
ps[i].className = "red";
}else{
ps[i].className = "green";
}
}
</script>
</body>
</html>
11. 给多个按钮注册点击事件,点击的那个变成红色
<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<style>
.bg{
background-color: pink;
}
</style>
<body>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<button>按钮</button>
<script>
//1. 给多个按钮注册点击事件,点击的那个变成红色
var buts = document.getElementsByTagName("button");
for(var i = 0 ;i<buts.length ; i++){
buts[i].onclick = function(){
// 指向当前的按钮
this.className = "bg";
}
}
</script>
</body>
</html>