/* 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 = 64; // Limit amount of snow falling at once (less = lower CPU use) this.animationInterval = 33; // 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 = true; // 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 = 8; // Max pixel width reserved for snow element this.flakeHeight = 8; // Max pixel height reserved for snow element this.vMaxX = 5; // Maximum X velocity range for snow this.vMaxY = 4; // Maximum Y velocity range for snow this.zIndex = 0; // 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=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 (yDiff0.998) { // ~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; istorm.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