1.上代码，复制粘贴即可
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>风</title>
<style>
*{padding: 0;margin: 0;}
html{pverflow:hidden}
</style>
</head>
<body>
<canvas id = "canvas" style="background: #111;"></canvas>
<script type="text/javascript">
window.onload = function(){
//获取画布对象
var canvas = document.getElementById("canvas");
//获取画布的上下文
var context = canvas.getContext("2d");
//获取浏览器屏幕的宽高
var W = window.innerWidth;
var H = window.innerHeight;
//设置canvas宽高
canvas.width = W;
canvas.height = H;
//每个文字的字体大小
var fontSize = 16;
//计算列
var colunms = Math.floor(W/fontSize);
//记录每列文字的y轴坐标
var drops = [];
//给每一个文字初始化一个起始点的位置
for(var i = 0; i<colunms; i++){
drops.push(0);
}
//运动的文字
var str = "i love you";
//4:fillText(str,x,y);原理就是去更改y的坐标位置
//绘图的函数
function draw(){
context.fillStyle = "rgba(0,0,0,0.05)";
context.fillRect(0,0,W,H);
//给字体设置样式
context.font = "700 "+fontSize +"px 微软雅黑";
//给字体添加颜色
context.fillStyle = "#00cc33";//可以rgb、hsl、标准色、十六制颜色
//写入画布中
for(var i = 0; i<colunms; i++){
var index = Math.floor(Math.random() * str.length);
var x = i*fontSize;
var y = drops[i] * fontSize;
context.fillText(str[index],x,y);
//如果改变时间，肯定就是改变每次他的起点
if(y >= canvas.height && Math.random() > 0.99){
drops[i] = 0;
}
drops[i]++;
}
}
function randColoe(){
var r = Math.floor(Math.random() * 256);
var g = Math.floor(Math.random() * 256);
var b = Math.floor(Math.random() * 256);
return "rgb(" + r + "," + g + "," + b + ")";
}
draw();
setInterval(draw,30);
}
</script>
</body>
</html>
