text: //fgnass.github.com/spin.js#v1.2.4
  (function(window, document, undefined) {
  
  /**
   * Copyright (c) 2011 Felix Gnass [fgnass at neteye dot de]
   * Licensed under the MIT license
   */
  
  	var prefixes = ['webkit', 'Moz', 'ms', 'O']; /* Vendor prefixes */
  	var animations = {}; /* Animation rules keyed by their name */
  	var useCssAnimations;
  
  	/**
  	 * Utility function to create elements. If no tag name is given,
  	 * a DIV is created. Optionally properties can be passed.
  	 */
  	function createEl(tag, prop) {
  		var el = document.createElement(tag || 'div');
  		var n;
  
  		for(n in prop) {
  			el[n] = prop[n];
  		}
  		return el;
  	}
  
  	/**
  	 * Appends children and returns the parent.
  	 */
  	function ins(parent /* child1, child2, ...*/) {
  		for (var i=1, n=arguments.length; i<n; i++) {
  			parent.appendChild(arguments[i]);
  		}
  		return parent;
  	}
  
  	/**
  	 * Insert a new stylesheet to hold the @keyframe or VML rules.
  	 */
  	var sheet = function() {
  		var el = createEl('style');
  		ins(document.getElementsByTagName('head')[0], el);
  		return el.sheet || el.styleSheet;
  	}();
  
  	/**
  	 * Creates an opacity keyframe animation rule and returns its name.
  	 * Since most mobile Webkits have timing issues with animation-delay,
  	 * we create separate rules for each line/segment.
  	 */
  	function addAnimation(alpha, trail, i, lines) {
  		var name = ['opacity', trail, ~~(alpha*100), i, lines].join('-');
  		var start = 0.01 + i/lines*100;
  		var z = Math.max(1-(1-alpha)/trail*(100-start) , alpha);
  		var prefix = useCssAnimations.substring(0, useCssAnimations.indexOf('Animation')).toLowerCase();
  		var pre = prefix && '-'+prefix+'-' || '';
  
  		if (!animations[name]) {
  			sheet.insertRule(
  				'@' + pre + 'keyframes ' + name + '{' +
  				'0%{opacity:'+z+'}' +
  				start + '%{opacity:'+ alpha + '}' +
  				(start+0.01) + '%{opacity:1}' +
  				(start+trail)%100 + '%{opacity:'+ alpha + '}' +
  				'100%{opacity:'+ z + '}' +
  				'}', 0);
  			animations[name] = 1;
  		}
  		return name;
  	}
  
  	/**
  	 * Tries various vendor prefixes and returns the first supported property.
  	 **/
  	function vendor(el, prop) {
  		var s = el.style;
  		var pp;
  		var i;
  
  		if(s[prop] !== undefined) return prop;
  		prop = prop.charAt(0).toUpperCase() + prop.slice(1);
  		for(i=0; i<prefixes.length; i++) {
  			pp = prefixes[i]+prop;
  			if(s[pp] !== undefined) return pp;
  		}
  	}
  
  	/**
  	 * Sets multiple style properties at once.
  	 */
  	function css(el, prop) {
  		for (var n in prop) {
  			el.style[vendor(el, n)||n] = prop[n];
  		}
  		return el;
  	}
  
  	/**
  	 * Fills in default values.
  	 */
  	function merge(obj) {
  		for (var i=1; i < arguments.length; i++) {
  			var def = arguments[i];
  			for (var n in def) {
  				if (obj[n] === undefined) obj[n] = def[n];
  			}
  		}
  		return obj;
  	}
  
  	/**
  	 * Returns the absolute page-offset of the given element.
  	 */
  	function pos(el) {
  		var o = {x:el.offsetLeft, y:el.offsetTop};
  		while((el = el.offsetParent)) {
  			o.x+=el.offsetLeft;
  			o.y+=el.offsetTop;
  		}
  		return o;
  	}
  
  	var defaults = {
  		lines: 12,            // The number of lines to draw
  		length: 7,            // The length of each line
  		width: 5,             // The line thickness
  		radius: 10,           // The radius of the inner circle
  		color: '#000',        // #rgb or #rrggbb
  		speed: 1,             // Rounds per second
  		trail: 100,           // Afterglow percentage
  		opacity: 1/4,         // Opacity of the lines
  		fps: 20,              // Frames per second when using setTimeout()
  		zIndex: 2e9,          // Use a high z-index by default
  		className: 'spinner', // CSS class to assign to the element
  		top: 'auto',          // center vertically
  		left: 'auto'          // center horizontally
  	};
  
  	/** The constructor */
  	var Spinner = function Spinner(o) {
  		if (!this.spin) return new Spinner(o);
  		this.opts = merge(o || {}, Spinner.defaults, defaults);
  	};
  
  	Spinner.defaults = {};
  	Spinner.prototype = {
  		spin: function(target) {
  			this.stop();
  			var self = this;
  			var o = self.opts;
  			var el = self.el = css(createEl(0, {className: o.className}), {position: 'relative', zIndex: o.zIndex});
  			var mid = o.radius+o.length+o.width;
  			var ep; // element position
  			var tp; // target position
  
  			if (target) {
  				target.insertBefore(el, target.firstChild||null);
  				tp = pos(target);
  				ep = pos(el);
  				css(el, {
  					left: (o.left == 'auto' ? tp.x-ep.x + (target.offsetWidth >> 1) : o.left+mid) + 'px',
  					top: (o.top == 'auto' ? tp.y-ep.y + (target.offsetHeight >> 1) : o.top+mid)  + 'px'
  				});
  			}
  
  			el.setAttribute('aria-role', 'progressbar');
  			self.lines(el, self.opts);
  
  			if (!useCssAnimations) {
  				// No CSS animation support, use setTimeout() instead
  				var i = 0;
  				var fps = o.fps;
  				var f = fps/o.speed;
  				var ostep = (1-o.opacity)/(f*o.trail / 100);
  				var astep = f/o.lines;
  
  				!function anim() {
  					i++;
  					for (var s=o.lines; s; s--) {
  						var alpha = Math.max(1-(i+s*astep)%f * ostep, o.opacity);
  						self.opacity(el, o.lines-s, alpha, o);
  					}
  					self.timeout = self.el && setTimeout(anim, ~~(1000/fps));
  				}();
  			}
  			return self;
  		},
  		stop: function() {
  			var el = this.el;
  			if (el) {
  				clearTimeout(this.timeout);
  				if (el.parentNode) el.parentNode.removeChild(el);
  				this.el = undefined;
  			}
  			return this;
  		},
  		lines: function(el, o) {
  			var i = 0;
  			var seg;
  
  			function fill(color, shadow) {
  				return css(createEl(), {
  					position: 'absolute',
  					width: (o.length+o.width) + 'px',
  					height: o.width + 'px',
  					background: color,
  					boxShadow: shadow,
  					transformOrigin: 'left',
  					transform: 'rotate(' + ~~(360/o.lines*i) + 'deg) translate(' + o.radius+'px' +',0)',
  					borderRadius: (o.width>>1) + 'px'
  				});
  			}
  			for (; i < o.lines; i++) {
  				seg = css(createEl(), {
  					position: 'absolute',
  					top: 1+~(o.width/2) + 'px',
  					transform: o.hwaccel ? 'translate3d(0,0,0)' : '',
  					opacity: o.opacity,
  					animation: useCssAnimations && addAnimation(o.opacity, o.trail, i, o.lines) + ' ' + 1/o.speed + 's linear infinite'
  				});
  				if (o.shadow) ins(seg, css(fill('#000', '0 0 4px ' + '#000'), {top: 2+'px'}));
  				ins(el, ins(seg, fill(o.color, '0 0 1px rgba(0,0,0,.1)')));
  			}
  			return el;
  		},
  		opacity: function(el, i, val) {
  			if (i < el.childNodes.length) el.childNodes[i].style.opacity = val;
  		}
  	};
  
  	/////////////////////////////////////////////////////////////////////////
  	// VML rendering for IE
  	/////////////////////////////////////////////////////////////////////////
  
  	/**
  	 * Check and init VML support
  	 */
  	!function() {
  		var s = css(createEl('group'), {behavior: 'url(#default#VML)'});
  		var i;
  
  		if (!vendor(s, 'transform') && s.adj) {
  
  			// VML support detected. Insert CSS rules ...
  			for (i=4; i--;) sheet.addRule(['group', 'roundrect', 'fill', 'stroke'][i], 'behavior:url(#default#VML)');
  
  			Spinner.prototype.lines = function(el, o) {
  				var r = o.length+o.width;
  				var s = 2*r;
  
  				function grp() {
  					return css(createEl('group', {coordsize: s +' '+s, coordorigin: -r +' '+-r}), {width: s, height: s});
  				}
  
  				var margin = -(o.width+o.length)*2+'px';
  				var g = css(grp(), {position: 'absolute', top: margin, left: margin});
  
  				var i;
  
  				function seg(i, dx, filter) {
  					ins(g,
  						ins(css(grp(), {rotation: 360 / o.lines * i + 'deg', left: ~~dx}),
  							ins(css(createEl('roundrect', {arcsize: 1}), {
  									width: r,
  									height: o.width,
  									left: o.radius,
  									top: -o.width>>1,
  									filter: filter
  								}),
  								createEl('fill', {color: o.color, opacity: o.opacity}),
  								createEl('stroke', {opacity: 0}) // transparent stroke to fix color bleeding upon opacity change
  							)
  						)
  					);
  				}
  
  				if (o.shadow) {
  					for (i = 1; i <= o.lines; i++) {
  						seg(i, -2, 'progid:DXImageTransform.Microsoft.Blur(pixelradius=2,makeshadow=1,shadowopacity=.3)');
  					}
  				}
  				for (i = 1; i <= o.lines; i++) seg(i);
  				return ins(el, g);
  			};
  			Spinner.prototype.opacity = function(el, i, val, o) {
  				var c = el.firstChild;
  				o = o.shadow && o.lines || 0;
  				if (c && i+o < c.childNodes.length) {
  					c = c.childNodes[i+o]; c = c && c.firstChild; c = c && c.firstChild;
  					if (c) c.opacity = val;
  				}
  			};
  		}
  		else {
  			useCssAnimations = vendor(s, 'animation');
  		}
  	}();
  
  	window.Spinner = Spinner;
  
  })(window, document);