用HTML5+CSS+JavaScript庆祝国庆
中华人民共和国的国庆日是每年的10月1日。
1949年10月1日，中华人民共和国中央人民政府成立，在首都北京天安门广场举行了开国大典，中央人民政府主席毛泽东庄严宣告中华人民共和国成立，并亲手升起了第一面五星红旗。这一历史性的时刻标志着新中国的诞生。1949年12月2日，中央人民政府委员会第四次会议接受全国政协的建议，通过了《关于中华人民共和国国庆日的决议》，决定每年10月1日为中华人民共和国国庆日。
国庆日这一天，全国各地都会举行各种庆祝活动，如悬挂国旗、唱国歌、文艺演出、烟花表演等方式来庆祝这一重要节日。
现在，让我们用HTML5+CSS+JavaScript庆祝中华人民共和国的国庆日。
先看用css3画五星红旗效果：
用css3画五星红旗源码如下：
<!DOCTYPE HTML>
<html>
<head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>CSS画五星红旗</title><style>.flag{width: 300px;height: 200px;background-color: red;position: relative;}body {display: flex;height: 100vh; /* 页面高度 */justify-content: center; /* 水平居中 */align-items: center; /* 垂直居中 */margin: 0; /* 去掉默认边距 */}.star{margin: 0 0;position: absolute;display: block;/* color: red; */width: 0;height: 0;border-right: 100px solid transparent;border-bottom: 70px solid yellow;/* */border-left: 100px solid transparent;transform: rotate(35deg);left: 20px;}.star:before {border-bottom: 80px solid yellow;border-left: 30px solid transparent;border-right: 30px solid transparent;position: absolute;height: 0;width: 0;top: -45px;left: -65px;display: block;content: '';transform: rotate(-35deg);}.star:after{content: '';margin: 0;position: absolute;display: block;/* color: red; */width: 0;height: 0;border-right: 100px solid transparent;border-bottom: 70px solid yellow;/* */border-left: 100px solid transparent;transform: rotate(-70deg);left: -107px;top: 5px;}.big{/* position: absolute; */transform: scale(.3) rotate(35deg);top: 10px;left: -50px;z-index: 3;}.little1{position: absolute;transform: scale(.1) rotate(-60deg);top: -15px;left: 5px;}.little2{position: absolute;transform: scale(.1) rotate(-45deg);top: 5px;left: 30px;}.little3{position: absolute;transform: scale(.1) rotate(35deg);top: 33px;left: 30px;}.little4{position: absolute;transform: scale(.1) rotate(60deg);top: 50px;left: 5px;}</style></head>
<body><div class="flag"><div class="star big"></div><div class="star little1"></div><div class="star little2"></div><div class="star little3"></div><div class="star little4"></div></div>
</body>
</html>
下面添加烟花效果烘托国庆气氛
先看国庆烟花效果：
国庆烟花源码如下：
<!DOCTYPE HTML>
<html>
<head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>国庆烟花气氛</title><style>body {display: flex;height: 100vh; /* 页面高度 */justify-content: center; /* 水平居中 */align-items: center; /* 垂直居中 */margin: 0; /* 去掉默认边距 */position: relative;overflow: hidden;background-color: #000; /* 背景设为黑色，模拟夜空 */}.flag {width: 300px;height: 200px;background-color: red;position: relative;z-index: 1;}.star {margin: 0 0;position: absolute;display: block;width: 0;height: 0;border-right: 100px solid transparent;border-bottom: 70px solid yellow;border-left: 100px solid transparent;transform: rotate(35deg);left: 20px;}.star:before {border-bottom: 80px solid yellow;border-left: 30px solid transparent;border-right: 30px solid transparent;position: absolute;height: 0;width: 0;top: -45px;left: -65px;display: block;content: '';transform: rotate(-35deg);}.star:after {content: '';margin: 0;position: absolute;display: block;width: 0;height: 0;border-right: 100px solid transparent;border-bottom: 70px solid yellow;border-left: 100px solid transparent;transform: rotate(-70deg);left: -107px;top: 5px;}.big {transform: scale(.3) rotate(35deg);top: 10px;left: -50px;z-index: 3;}.little1 {position: absolute;transform: scale(.1) rotate(-60deg);top: -15px;left: 5px;}.little2 {position: absolute;transform: scale(.1) rotate(-45deg);top: 5px;left: 30px;}.little3 {position: absolute;transform: scale(.1) rotate(35deg);top: 33px;left: 30px;}.little4 {position: absolute;transform: scale(.1) rotate(60deg);top: 50px;left: 5px;}canvas {position: absolute;top: 0;left: 0;width: 100%;height: 100%;pointer-events: none; /* 使canvas不会阻止点击事件 */}</style>
</head>
<body><canvas id="fireworks"></canvas><div class="flag"><div class="star big"></div><div class="star little1"></div><div class="star little2"></div><div class="star little3"></div><div class="star little4"></div></div><script>const canvas = document.getElementById('fireworks');const ctx = canvas.getContext('2d');canvas.width = window.innerWidth;canvas.height = window.innerHeight;function randomColor() {return `hsl(${Math.random() * 360}, 100%, 50%)`;}function Firework(x, y) {this.x = x;this.y = y;this.size = Math.random() * 10 + 5;this.speed = Math.random() * 6 + 2;this.angle = Math.random() * Math.PI * 2;this.color = randomColor();this.exploded = false;this.particles = [];this.update = function () {if (!this.exploded) {this.y -= this.speed;// 限制烟花的最大高度if (this.y < canvas.height * 0.2) { // 高度限制this.exploded = true;this.createParticles();}if (this.size > 0) {this.size -= 0.1;} else {this.exploded = true;this.createParticles();}} else {this.particles.forEach(p => p.update());}};this.createParticles = function () {const particleCount = Math.random() * 100 + 50;for (let i = 0; i < particleCount; i++) {this.particles.push(new Particle(this.x, this.y, this.color));}};this.draw = function () {if (!this.exploded) {if (this.size > 0) { // 仅在大小为正时绘制。ctx.fillStyle = this.color;ctx.beginPath();ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);ctx.fill();}} else {this.particles.forEach(p => p.draw());}};}function Particle(x, y, color) {this.x = x;this.y = y;// 将颜色分解为RGB，以便后续使用this.color = color.match(/\d+/g).map(Number);this.size = Math.random() * 3 + 2;this.speed = Math.random() * 3 + 1;this.angle = Math.random() * Math.PI * 2;this.alpha = 1;this.update = function () {this.x += Math.cos(this.angle) * this.speed;this.y += Math.sin(this.angle) * this.speed;this.alpha -= 0.02;};this.draw = function () {ctx.fillStyle = `rgba(${this.color.join(",")}, ${this.alpha})`;if (this.alpha > 0) { // 仅当透明度为正时绘制。ctx.beginPath();ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);ctx.fill();}};}const fireworks = [];function createFirework() {const firework = new Firework(Math.random() * canvas.width, canvas.height);fireworks.push(firework);}function animate() {ctx.clearRect(0, 0, canvas.width, canvas.height);fireworks.forEach((firework, index) => {firework.update();firework.draw();if (firework.exploded && firework.particles.length === 0) {fireworks.splice(index, 1);}});requestAnimationFrame(animate);}for (let i = 0; i < 5; i++) {createFirework();}animate();setInterval(createFirework, 1000);</script>
</body>
</html>