我刚刚偶然发现了一个代码笔 demo .然后代码在 codepen 窗口中工作正常。当我将它复制到本地 HTML 文件时，它停止工作了。这是所有组合在一个 .html 文件中的代码
<!DOCTYPE html>
<html>
<head>
<style>
body {
margin: 0;
overflow: hidden;
}
#myCanvas {
display: block;
}
#button {
font-family: "Gill Sans", "Gill Sans MT", Calibri, sans-serif;
position: absolute;
font-size: 1.5em;
text-transform: uppercase;
padding: 7px 20px;
left: 50%;
width: 200px;
margin-left: -100px;
top: 50%;
border-radius: 10px;
color: white;
text-shadow: -1px -1px 1px rgba(0,0,0,0.8);
border: 5px solid transparent;
border-bottom-color: rgba(0,0,0,0.35);
background: hsla(260, 100%, 50%, 1);
cursor: pointer;
animation: pulse 1s infinite alternate;
transition: background 0.4s, border 0.2s, margin 0.2s;
}
#button:hover {
background: hsla(220, 100%, 60%, 1);
margin-top: -1px;
animation: none;
}
#button:active {
border-bottom-width: 0;
margin-top: 5px;
}
@keyframes pulse {
0% {
margin-top: 0px;
}
100% {
margin-top: 6px;
}}
</style>
</head>
<body>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
<script>
window.requestAnimFrame = (function () {
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function (callback) {
window.setTimeout(callback, 1000 / 60);
};
})();
Math.randMinMax = function(min, max, round) {
var val = min + (Math.random() * (max - min));
if( round ) val = Math.round( val );
return val;
};
Math.TO_RAD = Math.PI/180;
Math.getAngle = function( x1, y1, x2, y2 ) {
var dx = x1 - x2,
dy = y1 - y2;
return Math.atan2(dy,dx);
};
Math.getDistance = function( x1, y1, x2, y2 ) {
var xs = x2 - x1,
ys = y2 - y1;
xs *= xs;
ys *= ys;
return Math.sqrt( xs + ys );
};
var FX = {};
(function() {
var canvas = document.getElementById('myCanvas'),
ctx = canvas.getContext('2d'),
lastUpdate = new Date(),
mouseUpdate = new Date(),
lastMouse = [],
width, height;
FX.particles = [];
setFullscreen();
document.getElementById('button').addEventListener('mousedown', buttonEffect);
function buttonEffect() {
var button = document.getElementById('button'),
height = button.offsetHeight,
left = button.offsetLeft,
top = button.offsetTop,
width = button.offsetWidth,
x, y, degree;
for(var i=0;i<40;i=i+1) {
if( Math.random() < 0.5 ) {
y = Math.randMinMax(top, top+height);
if( Math.random() < 0.5 ) {
x = left;
degree = Math.randMinMax(-45,45);
} else {
x = left + width;
degree = Math.randMinMax(135,225);
}
} else {
x = Math.randMinMax(left, left+width);
if( Math.random() < 0.5 ) {
y = top;
degree = Math.randMinMax(45,135);
} else {
y = top + height;
degree = Math.randMinMax(-135, -45);
}
}
createParticle({
x: x,
y: y,
degree: degree,
speed: Math.randMinMax(100, 150),
vs: Math.randMinMax(-4,-1)
});
}
}
window.setTimeout(buttonEffect, 100);
loop();
window.addEventListener('resize', setFullscreen );
function createParticle( args ) {
var options = {
x: width/2,
y: height/2,
color: 'hsla('+ Math.randMinMax(160, 290) +', 100%, 50%, '+(Math.random().toFixed(2))+')',
degree: Math.randMinMax(0, 360),
speed: Math.randMinMax(300, 350),
vd: Math.randMinMax(-90,90),
vs: Math.randMinMax(-8,-5)
};
for (key in args) {
options[key] = args[key];
}
FX.particles.push( options );
}
function loop() {
var thisUpdate = new Date(),
delta = (lastUpdate - thisUpdate) / 1000,
amount = FX.particles.length,
size = 2,
i = 0,
p;
ctx.fillStyle = 'rgba(15,15,15,0.25)';
ctx.fillRect(0,0,width,height);
ctx.globalCompositeStyle = 'lighter';
for(;i<amount;i=i+1) {
p = FX.particles[ i ];
p.degree += (p.vd * delta);
p.speed += (p.vs);// * delta);
if( p.speed < 0 ) continue;
p.x += Math.cos(p.degree * Math.TO_RAD) * (p.speed * delta);
p.y += Math.sin(p.degree * Math.TO_RAD) * (p.speed * delta);
ctx.save();
ctx.translate( p.x, p.y );
ctx.rotate( p.degree * Math.TO_RAD );
ctx.fillStyle = p.color;
ctx.fillRect( -size, -size, size*2, size*2 );
ctx.restore();
}
lastUpdate = thisUpdate;
requestAnimFrame( loop );
}
function setFullscreen() {
width = canvas.width = window.innerWidth;
height = canvas.height = window.innerHeight;
};
})();
</script>
<button id="button">click me</button>
<canvas id="myCanvas" width="500" height="500"></canvas>
</body>
</html>
最佳答案
您需要在$.ready() 中使用您的脚本代码喜欢，
$(function(){
window.requestAnimFrame = (function () {
....
....
})();
});
由于您的脚本首先加载但它没有找到任何 DOM 元素，因此它不起作用。
此外，您不需要包含 jquery，因为您没有在代码中使用任何 jquery 功能，所以请尝试一下，
<!DOCTYPE html>
<html>
<head>
<style>
// your style here
</style>
</head>
<body>
<button id="button">click me</button>
<canvas id="myCanvas" width="500" height="500"></canvas>
<script>
// and no need to include jquery if not used
// you script goes here after adding DOM elements
</script>
</body>
</html>
关于javascript - codepen 演示在本地浏览器中不起作用？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28081921/