html流星雨代码__中公优就业

品牌型号：联想小新Pro13/系统版本：windows10

基于HTML+CSS+JS实现流星雨特效实现，可用于移动开发以及网站背景图，具体代码如下：

<!doctype html>

<html>

<head>

<meta charset="utf-8" />

<title>流星雨</title>

<meta name="keywords" content="关键词，关键字">

<meta name="description" content="描述信息">

<style>

body {

margin: 0;

overflow: hidden;

}

</style>

</head>

<body>



<canvas width=400 height=400 style="background:#000000;" id="canvas"></canvas>



<script>

//获取画板

//doccument 当前文档

//getElement 获取一个标签

//ById 通过Id名称的方式

//var 声明一片空间

//var canvas 声明一片空间的名字叫做canvas

var canvas = document.getElementById("canvas");

//获取画板权限上下文

var ctx = canvas.getContext("2d");

//让画板的大小等于屏幕的大小

/*

思路：

1.获取屏幕对象

2.获取屏幕的尺寸

3.屏幕的尺寸赋值给画板

*/

//获取屏幕对象

var s = window.screen;

//获取屏幕的宽度和高度

var w = s.width;

var h = s.height;

//设置画板的大小

canvas.width = w;

canvas.height = h;

//设置文字大小

var fontSize = 14;

//计算一行有多少个文字取整数向下取整

var clos = Math.floor(w/fontSize);

//思考每一个字的坐标

//创建数组把clos 个 0 （y坐标存储起来）

var drops = [];

var str = "qwertyuiopasdfghjklzxcvbnm";

//往数组里面添加 clos 个 0

for(var i = 0;i<clos;i++) {

drops.push(0);

}

//绘制文字

function drawString() {

//给矩形设置填充色

ctx.fillStyle="rgba(0,0,0,0.05)"

//绘制一个矩形

ctx.fillRect(0,0,w,h);

//添加文字样式

ctx.font = "600 "+fontSize+"px 微软雅黑";

//设置文字颜色

ctx.fillStyle = "#00ff00";

for(var i = 0;i<clos;i++) {

//x坐标

var x = i*fontSize;

//y坐标

var y = drops[i]*fontSize;

//设置绘制文字

ctx.fillText(str[Math.floor(Math.random()*str.length)],x,y);

if(y>h&&Math.random()>0.99){

drops[i] = 0;

}

drops[i]++;

}

}

//定义一个定时器，每隔30毫秒执行一次

setInterval(drawString,30);

</script>

</body>

</html>

其它答案

牛仔很忙2020-06-22 18:56:36

<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<title>流星雨</title>

<script>

var context;

var arr = new Array();

var starCount = 800;

var rains = new Array();

var rainCount = 20;

function init() {

var stars = document.getElementById("stars");

windowWidth = window.innerWidth; //当前的窗口的高度

stars.width = windowWidth;

stars.height = window.innerHeight;

context = stars.getContext("2d");

}

//创建一个星星对象

var Star = function () {

this.x = windowWidth * Math.random();//横坐标

this.y = 5000 * Math.random();//纵坐标

this.text = ".";//文本

this.color = "white";//颜色

this.getColor = function () {

var _r = Math.random();

if (_r < 0.5) {

this.color = "#333";

} else {

this.color = "white";

}

}

//初始化

this.init = function () {

this.getColor();

}

//绘制

this.draw = function () {

context.fillStyle = this.color;

context.fillText(this.text, this.x, this.y);

}

}

//画月亮

function drawMoon() {

var moon = new Image();

moon.src = "./images/moon.jpg"

context.drawImage(moon, -5, -10);

}

//页面加载的时候

window.onload = function () {

init();

//画星星

for (var i = 0; i < starCount; i++) {

var star = new Star();

star.init();

star.draw();

arr.push(star);

}

//画流星

for (var i = 0; i < rainCount; i++) {

var rain = new MeteorRain();

rain.init();

rain.draw();

rains.push(rain);

}

drawMoon();//绘制月亮

playStars();//绘制闪动的星星

playRains();//绘制流星

}

//星星闪起来

function playStars() {

for (var n = 0; n < starCount; n++) {

arr[n].getColor();

arr[n].draw();

}

setTimeout("playStars()", 100);

}

/*流星雨开始*/

var MeteorRain = function () {

this.x = -1;

this.y = -1;

this.length = -1;//长度

this.angle = 30; //倾斜角度

this.width = -1;//宽度

this.height = -1;//高度

this.speed = 1;//速度

this.offset_x = -1;//横轴移动偏移量

this.offset_y = -1;//纵轴移动偏移量

this.alpha = 1; //透明度

this.color1 = "";//流星的色彩

this.color2 = ""; //流星的色彩

/****************初始化函数********************/

this.init = function () //初始化

{
this.getPos();
this.alpha = 1;//透明度
this.getRandomColor();
//最小长度，最大长度
var x = Math.random() * 80 + 150;
this.length = Math.ceil(x);
// x = Math.random()*10+30;
this.angle = 30; //流星倾斜角
x = Math.random() + 0.5;
this.speed = Math.ceil(x); //流星的速度
var cos = Math.cos(this.angle * 3.14 / 180);
var sin = Math.sin(this.angle * 3.14 / 180);
this.width = this.length * cos; //流星所占宽度
this.height = this.length * sin;//流星所占高度
this.offset_x = this.speed * cos;
this.offset_y = this.speed * sin;
}
/**************获取随机颜色函数*****************/
this.getRandomColor = function () {
var a = Math.ceil(255 - 240 * Math.random());
//中段颜色
this.color1 = "rgba(" + a + "," + a + "," + a + ",1)";
//结束颜色
this.color2 = "black";
}
/***************重新计算流星坐标的函数******************/
this.countPos = function ()//
{
//往左下移动,x减少，y增加
this.x = this.x - this.offset_x;
this.y = this.y + this.offset_y;
}
/*****************获取随机坐标的函数*****************/
this.getPos = function () //
{
//横坐标200--1200
this.x = Math.random() * window.innerWidth; //窗口高度
//纵坐标小于600
this.y = Math.random() * window.innerHeight; //窗口宽度
}
/****绘制流星***************************/
this.draw = function () //绘制一个流星的函数
{
context.save();
context.beginPath();
context.lineWidth = 1; //宽度
context.globalAlpha = this.alpha; //设置透明度
//创建横向渐变颜色,起点坐标至终点坐标
var line = context.createLinearGradient(this.x, this.y,
this.x + this.width,
this.y - this.height);
//分段设置颜色
line.addColorStop(0, "white");
line.addColorStop(0.3, this.color1);
line.addColorStop(0.6, this.color2);
context.strokeStyle = line;
//起点
context.moveTo(this.x, this.y);
//终点
context.lineTo(this.x + this.width, this.y - this.height);
context.closePath();
context.stroke();
context.restore();
}
this.move = function () {
//清空流星像素
var x = this.x + this.width - this.offset_x;
var y = this.y - this.height;
context.clearRect(x - 3, y - 3, this.offset_x + 5, this.offset_y + 5);
// context.strokeStyle="red";
// context.strokeRect(x,y-1,this.offset_x+1,this.offset_y+1);
//重新计算位置，往左下移动
this.countPos();
//透明度增加
this.alpha -= 0.002;
//重绘
this.draw();
}
}
//绘制流星
function playRains() {
for (var n = 0; n < rainCount; n++) {
var rain = rains[n];
rain.move();//移动
if (rain.y > window.inner

Height) {//超出界限后重来
context.clearRect(rain.x, rain.y - rain.height, rain.width, rain.height);
rains[n] = new MeteorRain();
rains[n].init();
}
}
setTimeout("playRains()", 2);
}
/*流星雨结束*/
</script>
<style type="text/css">
body {
background-color: black;
}
body, html {
width: 100%;
height: 100%;
overflow: hidden;
}
</style>
</head>
<body>
<canvas id="stars"></canvas>
</body>
</html>

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