Code javacript hiệu ứng hoa anh đào rơi
Chia sẻ
DevForum chia sẻ các bạn code javascript làm hiệu ứng Hoa đào rơi nhẹ nhàng không ảnh hưởng tốc độ website.
1. HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Hoa đào rơi - DevForum</title>
</head>
<body>
<img src="https://lh3.googleusercontent.com/--vCv4c2ydA4/VouNG4inXsI/AAAAAAAACds/sMkZeNpv62g/s0-Ic42/bg.png" style="width: 100%;" alt="Hoa đào rơi devforum">
</body>
</html>2. CSS
3. JAVASCRIPT
var snowStorm = (function(window, document) {
// --- common properties ---
this.autoStart = true; // Whether the snow should start automatically or not.
this.excludeMobile = true; // Snow is likely to be bad news for mobile phones' CPUs (and batteries.) Enable at your own risk.
this.flakesMax = 128; // Limit total amount of snow made (falling + sticking)
this.flakesMaxActive = 10; // Limit amount of snow falling at once (less = lower CPU use)
this.animationInterval = 40; // Theoretical "miliseconds per frame" measurement. 20 = fast + smooth, but high CPU use. 50 = more conservative, but slower
this.useGPU = true; // Enable transform-based hardware acceleration, reduce CPU load.
this.className = null; // CSS class name for further customization on snow elements
this.excludeMobile = true; // Snow is likely to be bad news for mobile phones' CPUs (and batteries.) By default, be nice.
this.flakeBottom = null; // Integer for Y axis snow limit, 0 or null for "full-screen" snow effect
this.followMouse = true; // Snow movement can respond to the user's mouse
this.snowColor = '#fff'; // Don't eat (or use?) yellow snow.
this.snowCharacter = '
'; // • = bullet, · is square on some systems etc.
this.snowStick = false; // Whether or not snow should "stick" at the bottom. When off, will never collect.
this.targetElement = null; // element which snow will be appended to (null = document.body) - can be an element ID eg. 'myDiv', or a DOM node reference
this.useMeltEffect = true; // When recycling fallen snow (or rarely, when falling), have it "melt" and fade out if browser supports it
this.useTwinkleEffect = false; // Allow snow to randomly "flicker" in and out of view while falling
this.usePositionFixed = false; // true = snow does not shift vertically when scrolling. May increase CPU load, disabled by default - if enabled, used only where supported
this.usePixelPosition = false; // Whether to use pixel values for snow top/left vs. percentages. Auto-enabled if body is position:relative or targetElement is specified.
// --- less-used bits ---
this.freezeOnBlur = true; // Only snow when the window is in focus (foreground.) Saves CPU.
this.flakeLeftOffset = 0; // Left margin/gutter space on edge of container (eg. browser window.) Bump up these values if seeing horizontal scrollbars.
this.flakeRightOffset = 0; // Right margin/gutter space on edge of container
this.flakeWidth = 17; // Max pixel width reserved for snow element
this.flakeHeight = 17; // Max pixel height reserved for snow element
this.vMaxX = 1; // Maximum X velocity range for snow
this.vMaxY = 2; // Maximum Y velocity range for snow
this.zIndex = 999; // CSS stacking order applied to each snowflake
// --- "No user-serviceable parts inside" past this point, yadda yadda ---
var storm = this,
features,
// UA sniffing and backCompat rendering mode checks for fixed position, etc.
isIE = navigator.userAgent.match(/msie/i),
isIE6 = navigator.userAgent.match(/msie 6/i),
isMobile = navigator.userAgent.match(/mobile|opera m(ob|in)/i),
isBackCompatIE = (isIE && document.compatMode === 'BackCompat'),
noFixed = (isBackCompatIE || isIE6),
screenX = null,
screenX2 = null,
screenY = null,
scrollY = null,
docHeight = null,
vRndX = null,
vRndY = null,
windOffset = 1,
windMultiplier = 2,
flakeTypes = 6,
fixedForEverything = false,
targetElementIsRelative = false,
opacitySupported = (function() {
try {
document.createElement('div').style.opacity = '0.5';
} catch (e) {
return false;
}
return true;
}()),
didInit = false,
docFrag = document.createDocumentFragment();
features = (function() {
var getAnimationFrame;
/**
* hat tip: paul irish
* http://paulirish.com/2011/requestanimationframe-for-smart-animating/
* https://gist.github.com/838785
*/
function timeoutShim(callback) {
window.setTimeout(callback, 1000 / (storm.animationInterval || 20));
}
var _animationFrame = (window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
timeoutShim);
// apply to window, avoid "illegal invocation" errors in Chrome
getAnimationFrame = _animationFrame ? function() {
return _animationFrame.apply(window, arguments);
} : null;
var testDiv;
testDiv = document.createElement('div');
function has(prop) {
// test for feature support
var result = testDiv.style[prop];
return (result !== undefined ? prop : null);
}
// note local scope.
var localFeatures = {
transform: {
ie: has('-ms-transform'),
moz: has('MozTransform'),
opera: has('OTransform'),
webkit: has('webkitTransform'),
w3: has('transform'),
prop: null // the normalized property value
},
getAnimationFrame: getAnimationFrame
};
localFeatures.transform.prop = (
localFeatures.transform.w3 ||
localFeatures.transform.moz ||
localFeatures.transform.webkit ||
localFeatures.transform.ie ||
localFeatures.transform.opera
);
testDiv = null;
return localFeatures;
}());
this.timer = null;
this.flakes = [];
this.disabled = false;
this.active = false;
this.meltFrameCount = 20;
this.meltFrames = [];
this.setXY = function(o, x, y) {
if (!o) {
return false;
}
if (storm.usePixelPosition || targetElementIsRelative) {
o.style.left = (x - storm.flakeWidth) + 'px';
o.style.top = (y - storm.flakeHeight) + 'px';
} else if (noFixed) {
o.style.right = (100 - (x / screenX * 100)) + '%';
// avoid creating vertical scrollbars
o.style.top = (Math.min(y, docHeight - storm.flakeHeight)) + 'px';
} else {
if (!storm.flakeBottom) {
// if not using a fixed bottom coordinate...
o.style.right = (100 - (x / screenX * 100)) + '%';
o.style.bottom = (100 - (y / screenY * 100)) + '%';
} else {
// absolute top.
o.style.right = (100 - (x / screenX * 100)) + '%';
o.style.top = (Math.min(y, docHeight - storm.flakeHeight)) + 'px';
}
}
};
this.events = (function() {
var old = (!window.addEventListener && window.attachEvent),
slice = Array.prototype.slice,
evt = {
add: (old ? 'attachEvent' : 'addEventListener'),
remove: (old ? 'detachEvent' : 'removeEventListener')
};
function getArgs(oArgs) {
var args = slice.call(oArgs),
len = args.length;
if (old) {
args[1] = 'on' + args[1]; // prefix
if (len > 3) {
args.pop(); // no capture
}
} else if (len === 3) {
args.push(false);
}
return args;
}
function apply(args, sType) {
var element = args.shift(),
method = [evt[sType]];
if (old) {
element[method](args[0], args[1]);
} else {
element[method].apply(element, args);
}
}
function addEvent() {
apply(getArgs(arguments), 'add');
}
function removeEvent() {
apply(getArgs(arguments), 'remove');
}
return {
add: addEvent,
remove: removeEvent
};
}());
function rnd(n, min) {
if (isNaN(min)) {
min = 0;
}
return (Math.random() * n) + min;
}
function plusMinus(n) {
return (parseInt(rnd(2), 10) === 1 ? n * -1 : n);
}
this.randomizeWind = function() {
var i;
vRndX = plusMinus(rnd(storm.vMaxX, 0.2));
vRndY = rnd(storm.vMaxY, 0.2);
if (this.flakes) {
for (i = 0; i < this.flakes.length; i++) {
if (this.flakes[i].active) {
this.flakes[i].setVelocities();
}
}
}
};
this.scrollHandler = function() {
var i;
// "attach" snowflakes to bottom of window if no absolute bottom value was given
scrollY = (storm.flakeBottom ? 0 : parseInt(window.scrollY || document.documentElement.scrollTop || (noFixed ? document.body.scrollTop : 0), 10));
if (isNaN(scrollY)) {
scrollY = 0; // Netscape 6 scroll fix
}
if (!fixedForEverything && !storm.flakeBottom && storm.flakes) {
for (i = 0; i < storm.flakes.length; i++) {
if (storm.flakes[i].active === 0) {
storm.flakes[i].stick();
}
}
}
};
this.resizeHandler = function() {
if (window.innerWidth || window.innerHeight) {
screenX = window.innerWidth - 16 - storm.flakeRightOffset;
screenY = (storm.flakeBottom || window.innerHeight);
} else {
screenX = (document.documentElement.clientWidth || document.body.clientWidth || document.body.scrollWidth) - (!isIE ? 8 : 0) - storm.flakeRightOffset;
screenY = storm.flakeBottom || document.documentElement.clientHeight || document.body.clientHeight || document.body.scrollHeight;
}
docHeight = document.body.offsetHeight;
screenX2 = parseInt(screenX / 2, 10);
};
this.resizeHandlerAlt = function() {
screenX = storm.targetElement.offsetWidth - storm.flakeRightOffset;
screenY = storm.flakeBottom || storm.targetElement.offsetHeight;
screenX2 = parseInt(screenX / 2, 10);
docHeight = document.body.offsetHeight;
};
this.freeze = function() {
// pause animation
if (!storm.disabled) {
storm.disabled = 1;
} else {
return false;
}
storm.timer = null;
};
this.resume = function() {
if (storm.disabled) {
storm.disabled = 0;
} else {
return false;
}
storm.timerInit();
};
this.toggleSnow = function() {
if (!storm.flakes.length) {
// first run
storm.start();
} else {
storm.active = !storm.active;
if (storm.active) {
storm.show();
storm.resume();
} else {
storm.stop();
storm.freeze();
}
}
};
this.stop = function() {
var i;
this.freeze();
for (i = 0; i < this.flakes.length; i++) {
this.flakes[i].o.style.display = 'none';
}
storm.events.remove(window, 'scroll', storm.scrollHandler);
storm.events.remove(window, 'resize', storm.resizeHandler);
if (storm.freezeOnBlur) {
if (isIE) {
storm.events.remove(document, 'focusout', storm.freeze);
storm.events.remove(document, 'focusin', storm.resume);
} else {
storm.events.remove(window, 'blur', storm.freeze);
storm.events.remove(window, 'focus', storm.resume);
}
}
};
this.show = function() {
var i;
for (i = 0; i < this.flakes.length; i++) {
this.flakes[i].o.style.display = 'block';
}
};
this.SnowFlake = function(type, x, y) {
var s = this;
this.type = type;
this.x = x || parseInt(rnd(screenX - 20), 10);
this.y = (!isNaN(y) ? y : -rnd(screenY) - 12);
this.vX = null;
this.vY = null;
this.vAmpTypes = [1]; // "amplification" for vX/vY (based on flake size/type)
this.vAmp = this.vAmpTypes[this.type] || 1;
this.melting = false;
this.meltFrameCount = storm.meltFrameCount;
this.meltFrames = storm.meltFrames;
this.meltFrame = 0;
this.twinkleFrame = 0;
this.active = 1;
this.fontSize = (10 + (this.type / 5) * 10);
this.o = document.createElement('div');
this.o.innerHTML = storm.snowCharacter;
if (storm.className) {
this.o.setAttribute('class', storm.className);
}
this.o.style.color = storm.snowColor;
this.o.style.position = (fixedForEverything ? 'fixed' : 'absolute');
if (storm.useGPU && features.transform.prop) {
// GPU-accelerated snow.
this.o.style[features.transform.prop] = 'translate3d(0px, 0px, 0px)';
}
this.o.style.width = storm.flakeWidth + 'px';
this.o.style.height = storm.flakeHeight + 'px';
this.o.style.fontFamily = 'arial,verdana';
this.o.style.cursor = 'default';
this.o.style.overflow = 'hidden';
this.o.style.fontWeight = 'normal';
this.o.style.zIndex = storm.zIndex;
docFrag.appendChild(this.o);
this.refresh = function() {
if (isNaN(s.x) || isNaN(s.y)) {
// safety check
return false;
}
storm.setXY(s.o, s.x, s.y);
};
this.stick = function() {
if (noFixed || (storm.targetElement !== document.documentElement && storm.targetElement !== document.body)) {
s.o.style.top = (screenY + scrollY - storm.flakeHeight) + 'px';
} else if (storm.flakeBottom) {
s.o.style.top = storm.flakeBottom + 'px';
} else {
s.o.style.display = 'none';
s.o.style.top = 'auto';
s.o.style.bottom = '0%';
s.o.style.position = 'fixed';
s.o.style.display = 'block';
}
};
this.vCheck = function() {
if (s.vX >= 0 && s.vX < 0.2) {
s.vX = 0.2;
} else if (s.vX < 0 && s.vX > -0.2) {
s.vX = -0.2;
}
if (s.vY >= 0 && s.vY < 0.2) {
s.vY = 0.2;
}
};
this.move = function() {
var vX = s.vX * windOffset,
yDiff;
s.x += vX;
s.y += (s.vY * s.vAmp);
if (s.x >= screenX || screenX - s.x < storm.flakeWidth) { // X-axis scroll check
s.x = 0;
} else if (vX < 0 && s.x - storm.flakeLeftOffset < -storm.flakeWidth) {
s.x = screenX - storm.flakeWidth - 1; // flakeWidth;
}
s.refresh();
yDiff = screenY + scrollY - s.y + storm.flakeHeight;
if (yDiff < storm.flakeHeight) {
s.active = 0;
if (storm.snowStick) {
s.stick();
} else {
s.recycle();
}
} else {
if (storm.useMeltEffect && s.active && s.type < 3 && !s.melting && Math.random() > 0.998) {
// ~1/1000 chance of melting mid-air, with each frame
s.melting = true;
s.melt();
// only incrementally melt one frame
// s.melting = false;
}
if (storm.useTwinkleEffect) {
if (s.twinkleFrame < 0) {
if (Math.random() > 0.97) {
s.twinkleFrame = parseInt(Math.random() * 8, 10);
}
} else {
s.twinkleFrame--;
if (!opacitySupported) {
s.o.style.visibility = (s.twinkleFrame && s.twinkleFrame % 2 === 0 ? 'hidden' : 'visible');
} else {
s.o.style.opacity = (s.twinkleFrame && s.twinkleFrame % 2 === 0 ? 0 : 1);
}
}
}
}
};
this.animate = function() {
// main animation loop
// move, check status, die etc.
s.move();
};
this.setVelocities = function() {
s.vX = vRndX + rnd(storm.vMaxX * 0.12, 0.1);
s.vY = vRndY + rnd(storm.vMaxY * 0.12, 0.1);
};
this.setOpacity = function(o, opacity) {
if (!opacitySupported) {
return false;
}
o.style.opacity = opacity;
};
this.melt = function() {
if (!storm.useMeltEffect || !s.melting) {
s.recycle();
} else {
if (s.meltFrame < s.meltFrameCount) {
s.setOpacity(s.o, s.meltFrames[s.meltFrame]);
s.o.style.fontSize = s.fontSize - (s.fontSize * (s.meltFrame / s.meltFrameCount)) + 'px';
s.o.style.lineHeight = storm.flakeHeight + 2 + (storm.flakeHeight * 0.75 * (s.meltFrame / s.meltFrameCount)) + 'px';
s.meltFrame++;
} else {
s.recycle();
}
}
};
this.recycle = function() {
s.o.style.display = 'none';
s.o.style.position = (fixedForEverything ? 'fixed' : 'absolute');
s.o.style.bottom = 'auto';
s.setVelocities();
s.vCheck();
s.meltFrame = 0;
s.melting = false;
s.setOpacity(s.o, 1);
s.o.style.padding = '0px';
s.o.style.margin = '0px';
s.o.style.fontSize = s.fontSize + 'px';
s.o.style.lineHeight = (storm.flakeHeight + 2) + 'px';
s.o.style.textAlign = 'center';
s.o.style.verticalAlign = 'baseline';
s.x = parseInt(rnd(screenX - storm.flakeWidth - 20), 10);
s.y = parseInt(rnd(screenY) * -1, 10) - storm.flakeHeight;
s.refresh();
s.o.style.display = 'block';
s.active = 1;
};
this.recycle(); // set up x/y coords etc.
this.refresh();
};
this.snow = function() {
var active = 0,
flake = null,
i, j;
for (i = 0, j = storm.flakes.length; i < j; i++) {
if (storm.flakes[i].active === 1) {
storm.flakes[i].move();
active++;
}
if (storm.flakes[i].melting) {
storm.flakes[i].melt();
}
}
if (active < storm.flakesMaxActive) {
flake = storm.flakes[parseInt(rnd(storm.flakes.length), 10)];
if (flake.active === 0) {
flake.melting = true;
}
}
if (storm.timer) {
features.getAnimationFrame(storm.snow);
}
};
this.mouseMove = function(e) {
if (!storm.followMouse) {
return true;
}
var x = parseInt(e.clientX, 10);
if (x < screenX2) {
windOffset = -windMultiplier + (x / screenX2 * windMultiplier);
} else {
x -= screenX2;
windOffset = (x / screenX2) * windMultiplier;
}
};
this.createSnow = function(limit, allowInactive) {
var i;
for (i = 0; i < limit; i++) {
storm.flakes[storm.flakes.length] = new storm.SnowFlake(parseInt(rnd(flakeTypes), 10));
if (allowInactive || i > storm.flakesMaxActive) {
storm.flakes[storm.flakes.length - 1].active = -1;
}
}
storm.targetElement.appendChild(docFrag);
};
this.timerInit = function() {
storm.timer = true;
storm.snow();
};
this.init = function() {
var i;
for (i = 0; i < storm.meltFrameCount; i++) {
storm.meltFrames.push(1 - (i / storm.meltFrameCount));
}
storm.randomizeWind();
storm.createSnow(storm.flakesMax); // create initial batch
storm.events.add(window, 'resize', storm.resizeHandler);
storm.events.add(window, 'scroll', storm.scrollHandler);
if (storm.freezeOnBlur) {
if (isIE) {
storm.events.add(document, 'focusout', storm.freeze);
storm.events.add(document, 'focusin', storm.resume);
} else {
storm.events.add(window, 'blur', storm.freeze);
storm.events.add(window, 'focus', storm.resume);
}
}
storm.resizeHandler();
storm.scrollHandler();
if (storm.followMouse) {
storm.events.add(isIE ? document : window, 'mousemove', storm.mouseMove);
}
storm.animationInterval = Math.max(20, storm.animationInterval);
storm.timerInit();
};
this.start = function(bFromOnLoad) {
if (!didInit) {
didInit = true;
} else if (bFromOnLoad) {
// already loaded and running
return true;
}
if (typeof storm.targetElement === 'string') {
var targetID = storm.targetElement;
storm.targetElement = document.getElementById(targetID);
if (!storm.targetElement) {
throw new Error('Snowstorm: Unable to get targetElement "' + targetID + '"');
}
}
if (!storm.targetElement) {
storm.targetElement = (document.body || document.documentElement);
}
if (storm.targetElement !== document.documentElement && storm.targetElement !== document.body) {
// re-map handler to get element instead of screen dimensions
storm.resizeHandler = storm.resizeHandlerAlt;
//and force-enable pixel positioning
storm.usePixelPosition = true;
}
storm.resizeHandler(); // get bounding box elements
storm.usePositionFixed = (storm.usePositionFixed && !noFixed && !storm.flakeBottom); // whether or not position:fixed is to be used
if (window.getComputedStyle) {
// attempt to determine if body or user-specified snow parent element is relatlively-positioned.
try {
targetElementIsRelative = (window.getComputedStyle(storm.targetElement, null).getPropertyValue('position') === 'relative');
} catch (e) {
// oh well
targetElementIsRelative = false;
}
}
fixedForEverything = storm.usePositionFixed;
if (screenX && screenY && !storm.disabled) {
storm.init();
storm.active = true;
}
};
function doDelayedStart() {
window.setTimeout(function() {
storm.start(true);
}, 20);
// event cleanup
storm.events.remove(isIE ? document : window, 'mousemove', doDelayedStart);
}
function doStart() {
if (!storm.excludeMobile || !isMobile) {
doDelayedStart();
}
// event cleanup
storm.events.remove(window, 'load', doStart);
}
// hooks for starting the snow
if (storm.autoStart) {
storm.events.add(window, 'load', doStart, false);
}
return this;
}(window, document));Mong bài viết giúp ích được các bạn phần nào trong thiết kế Web. Hãy nhấn nút Chia sẻđể mọi người cùng học hỏi kiến thức mới nhé. Cảm ơn các bạn đã quan tâm Forum.
