var snowStorm=null;function SnowStorm(){var imagePath='http://easyvn.net/tuyet/';var flakesMax=60;var flakesMaxActive=60;var vMaxX=2.5;var vMaxY=2.5;var usePNG=false;var flakeBottom=null;var snowStick=false;var snowCollect=false;var targetElement=null;var followMouse=true;var flakeTypes=6;var flakeWidth=8;var flakeHeight=8;var zIndex=0;var flakeLeftOffset=0;var flakeRightOffset=0;var addEvent=function(o,evtName,evtHandler){typeof(attachEvent)=='undefined'?o.addEventListener(evtName,evtHandler,false):o.attachEvent('on'+evtName,evtHandler);}
var removeEvent=function(o,evtName,evtHandler){typeof(attachEvent)=='undefined'?o.removeEventListener(evtName,evtHandler,false):o.detachEvent('on'+evtName,evtHandler);}
var classContains=function(o,cStr){return(typeof(o.className)!='undefined'?o.className.indexOf(cStr)+1:false);}
var s=this;var storm=this;this.timers=[];this.flakes=[];this.disabled=false;this.terrain=[];this.active=false;var isIE=navigator.userAgent.match(/msie/i);var isIE6=navigator.userAgent.match(/msie 6/i);var isOldIE=(isIE&&(isIE6||navigator.userAgent.match(/msie 5/i)));var isWin9X=navigator.appVersion.match(/windows 98/i);var isiPhone=navigator.userAgent.match(/iphone/i);var isOpera=navigator.userAgent.match(/opera/i);if(isOpera)isIE=false;var screenX=null;var screenX2=null;var screenY=null;var scrollY=null;var vRndX=null;var vRndY=null;var windOffset=1;var windMultiplier=2;var pngSupported=(!isIE||(isIE&&!isIE6&&!isOldIE));var docFrag=document.createDocumentFragment();this.oControl=null;if(flakeLeftOffset==null)flakeLeftOffset=0;if(flakeRightOffset==null)flakeRightOffset=0;function rnd(n,min){if(isNaN(min))min=0;return(Math.random()*n)+min;}
this.randomizeWind=function(){vRndX=plusMinus(rnd(vMaxX,0.2));vRndY=rnd(vMaxY,0.2);if(this.flakes){for(var i=0;i<this.flakes.length;i++){if(this.flakes[i].active)this.flakes[i].setVelocities();}}}
function plusMinus(n){return(parseInt(rnd(2))==1?n*-1:n);}
this.scrollHandler=function(){scrollY=(flakeBottom?0:parseInt(window.scrollY||document.documentElement.scrollTop||document.body.scrollTop));if(isNaN(scrollY))scrollY=0;if(!flakeBottom&&s.flakes){for(var i=0;i<s.flakes.length;i++){if(s.flakes[i].active==0)s.flakes[i].stick();}}}
this.resizeHandler=function(){if(window.innerWidth||window.innerHeight){screenX=window.innerWidth-(!isIE?16:2)-flakeRightOffset;screenY=(flakeBottom?flakeBottom:window.innerHeight);}else{screenX=(document.documentElement.clientWidth||document.body.clientWidth||document.body.scrollWidth)-(!isIE?8:0)-flakeRightOffset;screenY=flakeBottom?flakeBottom:(document.documentElement.clientHeight||document.body.clientHeight||document.body.scrollHeight);}
screenX2=parseInt(screenX/2);}
this.resizeHandlerAlt=function(){screenX=targetElement.offsetLeft+targetElement.offsetWidth-flakeRightOffset;screenY=flakeBottom?flakeBottom:targetElement.offsetTop+targetElement.offsetHeight;screenX2=parseInt(screenX/2);}
this.freeze=function(){if(!s.disabled){s.disabled=1;}else{return false;}
for(var i=0;i<s.timers.length;i++){clearInterval(s.timers[i]);}}
this.resume=function(){if(s.disabled){s.disabled=0;}else{return false;}
s.timerInit();}
this.toggleSnow=function(){if(!s.flakes.length){s.start();s.setControlActive(true);}else{s.active=!s.active;if(s.active){s.show();s.resume();s.setControlActive(true);}else{s.stop();s.freeze();s.setControlActive(false);}}}
this.setControlActive=function(bActive){}
this.stop=function(){this.freeze();for(var i=this.flakes.length;i--;){this.flakes[i].o.style.display='none';}
removeEvent(window,'scroll',s.scrollHandler);removeEvent(window,'resize',s.resizeHandler);if(!isIE){removeEvent(window,'blur',s.freeze);removeEvent(window,'focus',s.resume);}}
this.show=function(){for(var i=this.flakes.length;i--;){this.flakes[i].o.style.display='block';}}
this.SnowFlake=function(parent,type,x,y){var s=this;var storm=parent;this.type=type;this.x=x||parseInt(rnd(screenX-20));this.y=(!isNaN(y)?y:-rnd(screenY)-12);this.vX=null;this.vY=null;this.vAmpTypes=[2.0,1.0,1.25,1.0,1.5,1.75];this.vAmp=this.vAmpTypes[this.type];this.active=1;this.o=document.createElement('img');this.o.style.position='absolute';this.o.style.width=flakeWidth+'px';this.o.style.height=flakeHeight+'px';this.o.style.fontSize='1px';this.o.style.zIndex=zIndex;this.o.src=imagePath+this.type+(pngSupported&&usePNG?'.png':'.gif');docFrag.appendChild(this.o);this.refresh=function(){s.o.style.left=s.x+'px';s.o.style.top=s.y+'px';}
this.stick=function(){if(isIE6||isiPhone||(targetElement!=document.documentElement&&targetElement!=document.body)){s.o.style.top=(screenY+scrollY-flakeHeight-storm.terrain[Math.floor(s.x)])+'px';}else{s.o.style.display='none';s.o.style.top='auto';s.o.style.bottom='0px';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(){s.x+=s.vX*windOffset;s.y+=(s.vY*s.vAmp);s.refresh();if(s.vX&&screenX-s.x<flakeWidth+(s.vX*windOffset)){s.x=0;}else if((s.vX<0||windOffset<0)&&s.x-flakeLeftOffset<0-flakeWidth){s.x=screenX-flakeWidth;}
var yDiff=screenY+scrollY-s.y-storm.terrain[Math.floor(s.x)];if(yDiff<flakeHeight){s.active=0;if(snowCollect&&snowStick){var height=[0.75,1.5,0.75];for(var i=0;i<2;i++){storm.terrain[Math.floor(s.x)+i+2]+=height[i];}}
s.o.style.left=(s.x/screenX*100)+'%';if(!flakeBottom){if(snowStick){s.stick();}else{s.recycle();}}}}
this.animate=function(){s.move();}
this.setVelocities=function(){s.vX=vRndX+rnd(vMaxX*0.12,0.1);s.vY=vRndY+rnd(vMaxY*0.12,0.1);}
this.recycle=function(){s.o.style.display='none';s.o.style.position='absolute';s.o.style.bottom='auto';s.setVelocities();s.vCheck();s.x=parseInt(rnd(screenX-flakeWidth-20));s.y=parseInt(rnd(screenY)*-1)-flakeHeight;s.o.style.left=s.x+'px';s.o.style.top=s.y+'px';s.o.style.display='block';s.active=1;}
this.recycle();this.refresh();}
this.snow=function(){var active=0;var used=0;var waiting=0;for(var i=s.flakes.length;i--;){if(s.flakes[i].active==1){s.flakes[i].move();active++;}else if(s.flakes[i].active==0){used++;}else{waiting++;}}
if(snowCollect&&!waiting){s.createSnow(flakesMaxActive,true);}
if(active<flakesMaxActive){with(s.flakes[parseInt(rnd(s.flakes.length))]){if(!snowCollect&&active==0){recycle();}else if(active==-1){active=1;}}}}
this.mouseMove=function(e){if(!followMouse)return true;var x=parseInt(e.clientX);if(x<screenX2){windOffset=-windMultiplier+(x/screenX2*windMultiplier);}else{x-=screenX2;windOffset=(x/screenX2)*windMultiplier;}}
this.createSnow=function(limit,allowInactive){for(var i=0;i<limit;i++){s.flakes[s.flakes.length]=new s.SnowFlake(s,parseInt(rnd(flakeTypes)));if(allowInactive||i>flakesMaxActive)s.flakes[s.flakes.length-1].active=-1;}
targetElement.appendChild(docFrag);}
this.timerInit=function(){s.timers=(!isWin9X?[setInterval(s.snow,20)]:[setInterval(s.snow,75),setInterval(s.snow,25)]);}
this.init=function(){for(var i=0;i<2048;i++){s.terrain[i]=0;}
s.randomizeWind();s.createSnow(snowCollect?flakesMaxActive:flakesMaxActive*2);addEvent(window,'resize',s.resizeHandler);addEvent(window,'scroll',s.scrollHandler);if(!isIE){addEvent(window,'blur',s.freeze);addEvent(window,'focus',s.resume);}
s.resizeHandler();s.scrollHandler();if(followMouse){addEvent(document,'mousemove',s.mouseMove);}
s.timerInit();}
var didInit=false;this.start=function(bFromOnLoad){if(!didInit){didInit=true;}else if(bFromOnLoad){return true;}
if(typeof targetElement=='string'){targetElement=document.getElementById(targetElement);if(!targetElement)throw new Error('Snowstorm: Unable to get targetElement');}
if(!targetElement){targetElement=(!isIE?(document.documentElement?document.documentElement:document.body):document.body);}
if(targetElement!=document.documentElement&&targetElement!=document.body)s.resizeHandler=s.resizeHandlerAlt;s.resizeHandler();if(screenX&&screenY&&!s.disabled){s.init();s.active=true;}}
if(document.addEventListener){document.addEventListener('DOMContentLoaded',function(){s.start(true)},false);window.addEventListener('load',function(){s.start(true)},false);}else{addEvent(window,'load',function(){s.start(true)});}}
snowStorm=new SnowStorm();