先看看JS CSS HTML实现“代码雨”类似黑客帝国文字下落最终效果：
HTML代码：
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <link rel="stylesheet" type="text/css" href="css/ok.css" rel="external nofollow" > <title>code by-zhenyu.sha</title> </head> <body> <canvas id="canvas"></canvas> </body> <script src="http://www.jq22.com/jquery/jquery-1.10.2.js"></script> <script src="http://neilcarpenter.com/demos/canvas/matrix/stats.min.js"></script> <script type="text/javascript" src="js/ok.js"></script> </html>
js代码：
(function() {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for (var x = 0; x < vendors.length && !window.requestAnimationFrame; x) {
window.requestAnimationFrame = window[vendors[x] 'RequestAnimationFrame'];
window.cancelAnimationFrame = window[vendors[x] 'CancelAnimationFrame'] ||
window[vendors[x] 'CancelRequestAnimationFrame'];
}
if (!window.requestAnimationFrame)
window.requestAnimationFrame = function(callback, element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0, 16 - (currTime - lastTime));
var id = window.setTimeout(function() {
callback(currTime timeToCall);
},
timeToCall);
lastTime = currTime timeToCall;
return id;
};
if (!window.cancelAnimationFrame)
window.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}());
// stats
var stats = new Stats();
stats.setMode(0);
stats.domElement.style.position = 'absolute';
stats.domElement.style.left = '0px';
stats.domElement.style.top = '0px';
document.body.appendChild(stats.domElement);
var M = {
settings: {
COL_WIDTH: 20,
COL_HEIGHT: 25,
VELOCITY_PARAMS: {
min: 4,
max: 8
},
CODE_LENGTH_PARAMS: {
min: 20,
max: 40
}
},
animation: null,
c: null,
ctx: null,
lineC: null,
ctx2: null,
WIDTH: window.innerWidth,
HEIGHT: window.innerHeight,
COLUMNS: null,
canvii: [],
font: '30px matrix-code',
letters: ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '$', ' ', '-', '*', '/', '=', '%', '"', '\'', '#', '&', '_', '(', ')', ',', '.', ';', ':', '?', '!', '\\', '|', '{', '}', '<', '>', '[', ']', '^', '~'],
codes: [],
createCodeLoop: null,
codesCounter: 0,
init: function() {
M.c = document.getElementById('canvas');
M.ctx = M.c.getContext('2d');
M.c.width = M.WIDTH;
M.c.height = M.HEIGHT;
M.ctx.shadowBlur = 0;
M.ctx.fillStyle = '#000';
M.ctx.fillRect(0, 0, M.WIDTH, M.HEIGHT);
M.ctx.font = M.font;
M.COLUMNS = Math.ceil(M.WIDTH / M.settings.COL_WIDTH);
for (var i = 0; i < M.COLUMNS; i ) {
M.codes[i] = [];
M.codes[i][0] = {
'open': true,
'position': {
'x': 0,
'y': 0
},
'strength': 0
};
}
M.loop();
M.createLines();
M.createCode();
// not doing this, kills CPU
// M.swapCharacters();
window.onresize = function() {
window.cancelAnimationFrame(M.animation);
M.animation = null;
M.ctx.clearRect(0, 0, M.WIDTH, M.HEIGHT);
M.codesCounter = 0;
M.ctx2.clearRect(0, 0, M.WIDTH, M.HEIGHT);
M.WIDTH = window.innerWidth;
M.HEIGHT = window.innerHeight;
M.init();
};
},
loop: function() {
M.animation = requestAnimationFrame(function() {
M.loop();
});
M.draw();
stats.update();
},
draw: function() {
var velocity, height, x, y, c, ctx;
// slow fade BG colour
M.ctx.shadowColor = 'rgba(0, 0, 0, 0.5)';
M.ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
M.ctx.fillRect(0, 0, M.WIDTH, M.HEIGHT);
M.ctx.globalCompositeOperation = 'source-over';
for (var i = 0; i < M.COLUMNS; i ) {
// check member of array isn't undefined at this point
if (M.codes[i][0].canvas) {
velocity = M.codes[i][0].velocity;
height = M.codes[i][0].canvas.height;
x = M.codes[i][0].position.x;
y = M.codes[i][0].position.y - height;
c = M.codes[i][0].canvas;
ctx = c.getContext('2d');
M.ctx.drawImage(c, x, y, M.settings.COL_WIDTH, height);
if ((M.codes[i][0].position.y - height) < M.HEIGHT) {
M.codes[i][0].position.y = velocity;
} else {
M.codes[i][0].position.y = 0;
}
}
}
},
createCode: function() {
if (M.codesCounter > M.COLUMNS) {
clearTimeout(M.createCodeLoop);
return;
}
var randomInterval = M.randomFromInterval(0, 100);
var column = M.assignColumn();
if (column) {
var codeLength = M.randomFromInterval(M.settings.CODE_LENGTH_PARAMS.min, M.settings.CODE_LENGTH_PARAMS.max);
var codeVelocity = (Math.random() * (M.settings.VELOCITY_PARAMS.max - M.settings.VELOCITY_PARAMS.min)) M.settings.VELOCITY_PARAMS.min;
var lettersLength = M.letters.length;
M.codes[column][0].position = {
'x': (column * M.settings.COL_WIDTH),
'y': 0
};
M.codes[column][0].velocity = codeVelocity;
M.codes[column][0].strength = M.codes[column][0].velocity / M.settings.VELOCITY_PARAMS.max;
for (var i = 1; i <= codeLength; i ) {
var newLetter = M.randomFromInterval(0, (lettersLength - 1));
M.codes[column][i] = M.letters[newLetter];
}
M.createCanvii(column);
M.codesCounter ;
}
M.createCodeLoop = setTimeout(M.createCode, randomInterval);
},
createCanvii: function(i) {
var codeLen = M.codes[i].length - 1;
var canvHeight = codeLen * M.settings.COL_HEIGHT;
var velocity = M.codes[i][0].velocity;
var strength = M.codes[i][0].strength;
var text, fadeStrength;
var newCanv = document.createElement('canvas');
var newCtx = newCanv.getContext('2d');
newCanv.width = M.settings.COL_WIDTH;
newCanv.height = canvHeight;
for (var j = 1; j < codeLen; j ) {
text = M.codes[i][j];
newCtx.globalCompositeOperation = 'source-over';
newCtx.font = '30px matrix-code';
if (j < 5) {
newCtx.shadowColor = 'hsl(104, 79%, 74%)';
newCtx.shadowOffsetX = 0;
newCtx.shadowOffsetY = 0;
newCtx.shadowBlur = 10;
newCtx.fillStyle = 'hsla(104, 79%, ' (100 - (j * 5)) '%, ' strength ')';
} else if (j > (codeLen - 4)) {
fadeStrength = j / codeLen;
fadeStrength = 1 - fadeStrength;
newCtx.shadowOffsetX = 0;
newCtx.shadowOffsetY = 0;
newCtx.shadowBlur = 0;
newCtx.fillStyle = 'hsla(104, 79%, 74%, ' (fadeStrength 0.3) ')';
} else {
newCtx.shadowOffsetX = 0;
newCtx.shadowOffsetY = 0;
newCtx.shadowBlur = 0;
newCtx.fillStyle = 'hsla(104, 79%, 74%, ' strength ')';
}
newCtx.fillText(text, 0, (canvHeight - (j * M.settings.COL_HEIGHT)));
}
M.codes[i][0].canvas = newCanv;
},
swapCharacters: function() {
var randomCodeIndex;
var randomCode;
var randomCodeLen;
var randomCharIndex;
var newRandomCharIndex;
var newRandomChar;
for (var i = 0; i < 20; i ) {
randomCodeIndex = M.randomFromInterval(0, (M.codes.length - 1));
randomCode = M.codes[randomCodeIndex];
randomCodeLen = randomCode.length;
randomCharIndex = M.randomFromInterval(2, (randomCodeLen - 1));
newRandomCharIndex = M.randomFromInterval(0, (M.letters.length - 1));
newRandomChar = M.letters[newRandomCharIndex];
randomCode[randomCharIndex] = newRandomChar;
}
M.swapCharacters();
},
createLines: function() {
M.linesC = document.createElement('canvas');
M.linesC.width = M.WIDTH;
M.linesC.height = M.HEIGHT;
M.linesC.style.position = 'absolute';
M.linesC.style.top = 0;
M.linesC.style.left = 0;
M.linesC.style.zIndex = 10;
document.body.appendChild(M.linesC);
var linesYBlack = 0;
var linesYWhite = 0;
M.ctx2 = M.linesC.getContext('2d');
M.ctx2.beginPath();
M.ctx2.lineWidth = 1;
M.ctx2.strokeStyle = 'rgba(0, 0, 0, 0.7)';
while (linesYBlack < M.HEIGHT) {
M.ctx2.moveTo(0, linesYBlack);
M.ctx2.lineTo(M.WIDTH, linesYBlack);
linesYBlack = 5;
}
M.ctx2.lineWidth = 0.15;
M.ctx2.strokeStyle = 'rgba(255, 255, 255, 0.7)';
while (linesYWhite < M.HEIGHT) {
M.ctx2.moveTo(0, linesYWhite 1);
M.ctx2.lineTo(M.WIDTH, linesYWhite 1);
linesYWhite = 5;
}
M.ctx2.stroke();
},
assignColumn: function() {
var randomColumn = M.randomFromInterval(0, (M.COLUMNS - 1));
if (M.codes[randomColumn][0].open) {
M.codes[randomColumn][0].open = false;
} else {
return false;
}
return randomColumn;
},
randomFromInterval: function(from, to) {
return Math.floor(Math.random() * (to - from 1) from);
},
snapshot: function() {
window.open(M.c.toDataURL());
}
};
function eventListenerz() {
var controlToggles = document.getElementsByClassName('toggle-info');
var controls = document.getElementById('info');
var snapshotBtn = document.getElementById('snapshot');
function toggleControls(e) {
e.preventDefault();
controls.className = controls.className === 'closed' ? '' : 'closed';
}
for (var j = 0; j < 2; j ) {
controlToggles[j].addEventListener('click', toggleControls, false);
}
snapshotBtn.addEventListener('click', M.snapshot, false);
}
window.onload = function() {
M.init();
eventListenerz();
};
css代码：
@import url("http://fonts.googleapis.com/css?family=Carrois Gothic");
@font-face {
font-family: 'matrix-code';
src: url('http://neilcarpenter.com/demos/canvas/matrix/font/matrix-code.eot?#iefix') format('embedded-opentype'), url('http://neilcarpenter.com/demos/canvas/matrix/font/matrix-code.woff') format('woff'), url('http://neilcarpenter.com/demos/canvas/matrix/font/matrix-code.ttf') format('truetype'), url('http://neilcarpenter.com/demos/canvas/matrix/font/matrix-code.svg#svgFontName') format('svg');
}
html,
body {
-webkit-font-smoothing: antialiased;
font: normal 12px/14px "Carrois Gothic", sans-serif;
width: 100%;
height: 100%;
margin: 0;
overflow: hidden;
color: #fff;
-webkit-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}
body {
background: black;
}
#stats {
z-index: 100;
}
#info {
background: rgba(0, 0, 0, 0.7);
position: fixed;
bottom: 0;
left: 0px;
width: 250px;
padding: 10px 20px 20px;
z-index: 100;
-webkit-transform-origin: bottom center;
-moz-transform-origin: bottom center;
-o-transform-origin: bottom center;
transform-origin: bottom center;
-webkit-transform: rotate(0deg);
-moz-transform: rotate(0deg);
-o-transform: rotate(0deg);
transform: rotate(0deg);
-webkit-transition: -webkit-transform .5s ease-in-out;
-moz-transition: -moz-transform .5s ease-in-out;
-o-transition: -o-transform .5s ease-in-out;
transition: transform .5s ease-in-out;
}
#info.closed {
-webkit-transform: rotate(180deg);
-moz-transform: rotate(180deg);
-o-transform: rotate(180deg);
transform: rotate(180deg);
}
.toggle-info {
position: absolute;
display: block;
height: 10px;
background: rgba(0, 0, 0, 0.8);
width: 290px;
left: 0;
text-align: center;
padding: 3px 0 7px;
text-decoration: none;
color: white;
text-shadow: none;
}
.toggle-info:hover {
background: rgb(0, 0, 0);
}
#close {
top: -20px;
}
#open {
bottom: -20px;
-webkit-transform: rotate(-180deg);
-moz-transform: rotate(-180deg);
-o-transform: rotate(-180deg);
transform: rotate(-180deg);
}
button {
background: rgba(255, 255, 255, 0.2);
color: #fff;
border: 0;
border-radius: 2px;
padding: 7px 10px;
box-shadow: 0 0 3px 0px rgba(255, 255, 255, 0.3);
cursor: pointer;
}
button:hover {
background: rgba(255, 255, 255, 0.1);
}
pa {
color: #fff;
}
pa:hover {
color: #EFFDEB;
text-shadow: 0px 0px 5px #75AD61;
}
本文介绍了使用JS CSS HTML实现“代码雨”类似黑客帝国文字下落效果的代码实例，更多JS特效请查看下面的相关链接