效果展示
其余的效果，大家自己去体验叭！
代码
下雪.html
<!doctype html><html><head><meta charset="utf-8"><title>雪花——追光者♂</title><script type="text/javascript" src="js/jquery.min.js"></script><style>html,body { width: 100%; height: 100%; margin: 0; padding: 0; overflow: hidden;}.container{ width: 100%; height: 100%; margin: 0; padding: 0;}</style></head><body><div id="jsi-snow-container" class="container"></div><script>var RENDERER = {SNOW_COUNT: {INIT : 100, DELTA : 1},BACKGROUND_COLOR : 'hsl(%h, 50%, %l%)', INIT_HUE : 180,DELTA_HUE : 0.1,init : function(){this.setParameters();this.reconstructMethod();this.createSnow(this.SNOW_COUNT.INIT * this.countRate, true);this.render();},setParameters : function(){this.$window = $(window);this.$container = $('#jsi-snow-container');this.width = this.$container.width();this.height = this.$container.height();this.center = {x : this.width / 2, y : this.height / 2};this.countRate = this.width * this.height / 500 / 500;this.canvas = $('<canvas />').attr({width : this.width, height : this.height}).appendTo(this.$container).get(0);this.context = this.canvas.getContext('2d');this.radius = Math.sqrt(this.center.x * this.center.x + this.center.y * this.center.y);this.hue = this.INIT_HUE;this.snows = [];},reconstructMethod : function(){this.render = this.render.bind(this);},createSnow : function(count, toRandomize){for(var i = 0; i < count; i++){this.snows.push(new SNOW(this.width, this.height, this.center, toRandomize));}},render : function(){requestAnimationFrame(this.render);var gradient = this.context.createRadialGradient(this.center.x, this.center.y, 0, this.center.x, this.center.y, this.radius),backgroundColor = this.BACKGROUND_COLOR.replace('%h', this.hue);gradient.addColorStop(0, backgroundColor.replace('%l', 30));gradient.addColorStop(0.2, backgroundColor.replace('%l', 20));gradient.addColorStop(1, backgroundColor.replace('%l', 5));this.context.fillStyle = gradient;this.context.fillRect(0, 0, this.width, this.height);for(var i = this.snows.length - 1; i >= 0; i--){if(!this.snows[i].render(this.context)){this.snows.splice(i, 1);}}this.hue += this.DELTA_HUE;this.hue %= 360;this.createSnow(this.SNOW_COUNT.DELTA, false);}};var SNOW = function(width, height, center, toRandomize){this.width = width;this.height = height;this.center = center;this.init(toRandomize);};SNOW.prototype = {RADIUS : 20,OFFSET : 4,INIT_POSITION_MARGIN : 20,COLOR : 'rgba(255, 255, 255, 0.8)',TOP_RADIUS : {MIN : 1, MAX : 3},SCALE : {INIT : 0.04, DELTA : 0.01},DELTA_ROTATE : {MIN : -Math.PI / 180 / 2, MAX : Math.PI / 180 / 2},THRESHOLD_TRANSPARENCY : 0.7,VELOCITY : {MIN : -1, MAX : 1},LINE_WIDTH : 2,BLUR : 10,init : function(toRandomize){this.setParameters(toRandomize);this.createSnow();},setParameters : function(toRandomize){if(!this.canvas){this.radius = this.RADIUS + this.TOP_RADIUS.MAX * 2 + this.LINE_WIDTH;this.length = this.radius * 2;this.canvas = $('<canvas />').attr({width : this.length, height : this.length}).get(0);this.context = this.canvas.getContext('2d');}this.topRadius = this.getRandomValue(this.TOP_RADIUS);var theta = Math.PI * 2 * Math.random();this.x = this.center.x + this.INIT_POSITION_MARGIN * Math.cos(theta);this.y = this.center.y + this.INIT_POSITION_MARGIN * Math.sin(theta);this.vx = this.getRandomValue(this.VELOCITY);this.vy = this.getRandomValue(this.VELOCITY);this.deltaRotate = this.getRandomValue(this.DELTA_ROTATE);this.scale = this.SCALE.INIT;this.deltaScale = 1 + this.SCALE.DELTA * 500 / Math.max(this.width, this.height);this.rotate = 0;if(toRandomize){for(var i = 0, count = Math.random() * 1000; i < count; i++){this.x += this.vx; this.y += this.vy; this.scale *= this.deltaScale; this.rotate += this.deltaRotate;}}},getRandomValue : function(range){return range.MIN + (range.MAX - range.MIN) * Math.random();},createSnow : function(){this.context.clearRect(0, 0, this.length, this.length);this.context.save();this.context.beginPath();this.context.translate(this.radius, this.radius);this.context.strokeStyle = this.COLOR;this.context.lineWidth = this.LINE_WIDTH;this.context.shadowColor = this.COLOR;this.context.shadowBlur = this.BLUR;var angle60 = Math.PI / 180 * 60,sin60 = Math.sin(angle60),cos60 = Math.cos(angle60),threshold = Math.random() * this.RADIUS / this.OFFSET | 0,rate = 0.5 + Math.random() * 0.5,offsetY = this.OFFSET * Math.random() * 2,offsetCount = this.RADIUS / this.OFFSET;for(var i = 0; i < 6; i++){this.context.save();this.context.rotate(angle60 * i);for(var j = 0; j <= threshold; j++){var y = -this.OFFSET * j;this.context.moveTo(0, y);this.context.lineTo(y * sin60, y * cos60);}for(var j = threshold; j < offsetCount; j++){var y = -this.OFFSET * j,x = j * (offsetCount - j + 1) * rate;this.context.moveTo(x, y - offsetY);this.context.lineTo(0, y);this.context.lineTo(-x, y - offsetY);}this.context.moveTo(0, 0);this.context.lineTo(0, -this.RADIUS);this.context.arc(0, -this.RADIUS - this.topRadius, this.topRadius, Math.PI / 2, Math.PI * 2.5, false);this.context.restore();}this.context.stroke();this.context.restore();},render : function(context){context.save();if(this.scale > this.THRESHOLD_TRANSPARENCY){context.globalAlpha = Math.max(0, (1 - this.scale) / (1 - this.THRESHOLD_TRANSPARENCY));if(this.scale > 1 || this.x < -this.radius || this.x > this.width + this.radius || this.y < -this.radius || this.y > this.height + this.radius){context.restore();return false;}}context.translate(this.x, this.y);context.rotate(this.rotate);context.scale(this.scale, this.scale);context.drawImage(this.canvas, -this.radius, -this.radius);context.restore(); this.x += this.vx; this.y += this.vy; this.scale *= this.deltaScale; this.rotate += this.deltaRotate; return true;}};$(function(){RENDERER.init();});</script></body></html>另外还有一个jqery.min.js的小组件，相信大家都很熟悉，可以自行下载。我也将整个源文件上传到“资源”中啦！欢迎大家下载！