<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>下雪效果</title><script type="text/javascript" language="javascript">(function(){function k(a,b,c){if(a.addEventListener){a.addEventListener(b,c,false);}else{a.attachEvent&&a.attachEvent("on"+b,c)}}function g(a){if(typeof window.onload!="function"){window.onload=a;}else{var b=window.onload;window.onload=function(){b();a();}}}function h(){var a={};for(type in{Top:"",Left:""}){var b=type=="Top"?"Y":"X";if(typeof window["page"+b+"Offset"]!="undefined"){a[type.toLowerCase()]=window["page"+b+"Offset"];}else{b=document.documentElement.clientHeight?document.documentElement:document.body; a[type.toLowerCase()]=b["scroll"+type];}}return a;}function l(){var a=document.body,b;if(window.innerHeight){b=window.innerHeight;}else{if(a.parentElement.clientHeight){b=a.parentElement.clientHeight;}else{if(a&&a.clientHeight){b=a.clientHeight;}}}return b;}function i(a){this.parent=document.body;this.createEl(this.parent,a);this.size=Math.random()*5+5;this.el.style.width=Math.round(this.size)+"px";this.el.style.height=Math.round(this.size)+"px";this.maxLeft=document.body.offsetWidth-this.size;this.maxTop=document.body.offsetHeight- this.size;this.left=Math.random()*this.maxLeft;this.top=h().top+1;this.angle=1.4+0.2*Math.random();this.minAngle=1.4;this.maxAngle=1.6;this.angleDelta=0.01*Math.random();this.speed=2+Math.random()}var j=false;g(function(){j=true});var f=true;window.createSnow=function(a,b){if(j){var c=[];m=setInterval(function(){f&&b>c.length&&Math.random()<b*0.0025&&c.push(new i(a));!f&&!c.length&&clearInterval(m);for(var e=h().top,n=l(),d=c.length-1;d>=0;d--){if(c[d])if(c[d].top<e||c[d].top+c[d].size+1>e+n){c[d].remove(); c[d]=null;c.splice(d,1);}else{c[d].move();c[d].draw();}}},40);k(window,"scroll",function(){for(var e=c.length-1;e>=0;e--){c[e].draw();}})}else{g(function(){createSnow(a,b);})}};window.removeSnow=function(){f=false;};i.prototype={createEl:function(a,b){this.el=document.createElement("img");this.el.setAttribute("src",b+"http://mimg.127.net/hxm/quan/hd/111207_sdj/style/img/snow.gif");this.el.style.position="absolute";this.el.style.display="block";this.el.style.zIndex="99999";this.parent.appendChild(this.el)},move:function(){if(this.angle< this.minAngle||this.angle>this.maxAngle)this.angleDelta=-this.angleDelta;this.angle+=this.angleDelta;this.left+=this.speed*Math.cos(this.angle*Math.PI);this.top-=this.speed*Math.sin(this.angle*Math.PI);if(this.left<0){this.left=this.maxLeft;}else{if(this.left>this.maxLeft)this.left=0}},draw:function(){this.el.style.top=Math.round(this.top)+"px";this.el.style.left=Math.round(this.left)+"px"},remove:function(){this.parent.removeChild(this.el);this.parent=this.el=null}}})();createSnow("", 80);</script></head><body style="background-color:#77aac2"></body></html>相关资料：https://jucelin.com/snow-js.html
下雪的js代码
原文地址：https://www.cnblogs.com/time20181212/p/js20181212.html