效果图
代码
<!DOCTYPE html>
<html lang="en">
<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>
body {
margin: 0;
padding: 0;
}
canvas {
width: 100%;
height: 100%;
}
</style>
</head>
<body>
<canvas style="background:#111"></canvas>
<script>
//获取画布对象
var can = document.querySelector("canvas");
//获取画布的上下文
var ctx = can.getContext("2d");
//设置canvas的宽度和高度
can.width = window.innerWidth;
can.height = window.innerHeight;
//每个文字的字体大小
var fontSize = 16;
//计算列
var colunms = Math.floor(window.innerWidth / fontSize);
//记录每列文字的y轴坐标
var arr = [];
//给每一个文字初始化一个起始点的位置
for (var i = 0; i < colunms; i++) {
arr.push(0);
}
//运动的文字
var str = "you are a silly";
//绘画的函数
function draw() {
//布满全屏的黑色遮罩层
ctx.fillStyle = "rgba(0,0,0,0.05)";
ctx.fillRect(0, 0, window.innerWidth, window.innerHeight);
//给字体设置样式
ctx.font = "700 " + fontSize + "px 微软雅黑";
//给字体添加颜色
ctx.fillStyle = "#00cc33";
//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 = arr[i] * fontSize;
ctx.fillText(str[index], x, y);
//如果文字的Y轴坐标大于画布的高度，1/100*colunms概率将该文字的Y轴坐标重置为0
if (y >= can.height && Math.random() > 0.99) {
arr[i] = 0;
}
//文字Y轴坐标+1
arr[i]++;
}
}
draw();
setInterval(draw, 30);
</script>
</body>
</html>
