最近学习了HTML，今天写个HTML代码雨，然后下面用HTML和js也写了一个，给自己留点笔记
先看看效果
1、绿色：
2、彩色：
3、背景色：
4、绿色逐渐变浅：
源代码：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<title>Code -by ZhenYu.Sha</title>
<style type="text/css">
html, body {
width: 100%;
height: 100%;
}
body {
background: #000;
overflow: hidden;
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<canvas id="cvs"></canvas>
<script type="text/javascript">
var cvs = document.getElementById("cvs");
var ctx = cvs.getContext("2d");
var cw = cvs.width = document.body.clientWidth;
var ch = cvs.height = document.body.clientHeight;
//动画绘制对象
var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
var codeRainArr = []; //代码雨数组
var cols = parseInt(cw / 14); //代码雨列数
var step = 16; //步长，每一列内部数字之间的上下间隔
ctx.font = "bold 26px microsoft yahei"; //声明字体，个人喜欢微软雅黑 function createColorCv() {
//画布基本颜色
ctx.fillStyle = "#242424";
ctx.fillRect(0, 0, cw, ch);
}
//创建代码雨
function createCodeRain() {
for (var n = 0; n < cols; n++) {
var col = [];
//基础位置，为了列与列之间产生错位
var basePos = parseInt(Math.random() * 300);
//随机速度 3~13之间
var speed = parseInt(Math.random() * 10) + 3;
//每组的x轴位置随机产生
var colx = parseInt(Math.random() * cw)
//绿色随机
var rgbr = 0;
var rgbg = parseInt(Math.random() * 255);
var rgbb = 0;
//ctx.fillStyle = "rgb("+r+','+g+','+b+")"
for (var i = 0; i < parseInt(ch / step) / 2; i++) {
var code = {
x: colx,
y: -(step * i) - basePos,
speed: speed,
// text : parseInt(Math.random()*10)%2 == 0 ? 0 : 1 //随机生成0或者1
text: ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "s", "t", "u", "v", "w", "x", "y", "z"][parseInt(Math.random() * 11)], //随机生成字母数组中的一个
