效果图

wKiom1h_PGbiWkjxAAKfAHBIIkA839.png-wh_50

html结构

<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<meta http-equiv="X-UA-Compatible" content="IE=edge">

<title>canvas33</title>

<link rel="stylesheet" href="">

</head>

<body>

<canvas id="canvas" style ="border:1px solid #aaa;diplay:block;margin:50px auto;">

当前浏览器不支持canvas,请更换浏览器后再试

</canvas>

</body>

</html>

js脚本

<script>

window.onload = function(){

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

canvas.width  = 1200;

canvas.height = 800;


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

context.globalAlpha = 0.8;

for(var i = 0;i<100;i++){

var R = Math.floor(Math.random()*255);

var G = Math.floor(Math.random()*255);

var B = Math.floor(Math.random()*255);


context.fillStyle = "rgb("+R+","+G+","+B+")";


context.beginPath();

context.arc(Math.random()*canvas.width,Math.random()*canvas.height,Math.random()*100,0,Math.PI*2);

context.fill();

}

}

</script>

QQ截图20181014143201.jpg