<!DOCTYPE html>
<html lang="en" class="fuelux">
<head>
<meta charset="utf-8">
<title>Require</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="ladda.css" rel="stylesheet">
<style type="text/css">
body {
padding-bottom: 200px;
}
</style>
</head>

<body>

<div class="container">

<section>
<button class="ladda-button blue slide-right"><span class="ladda-label">Submit</span><span class="ladda-spinner"></span></button>
</section>
<section>
<button class="ladda-button blue slide-right"><span class="ladda-label">Submit</span><span class="ladda-spinner"></span></button>
</section>
</div>

<script src="//requirejs.org/docs/release/2.1.6/minified/require.js"></script>

<script>
//https://github.com/requirejs/example-jquery-cdn  
requirejs.config({
    //"baseUrl": "js/lib",
    enforceDefine: true,
    "paths": {
      "jquery": "//ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min",
      "spin": "spin",
      "ladda": "ladda"
    },
    shim: {
		"spin": {exports: "Spinner"},
		"ladda": {
            depends: "spin",
            exports: "Ladda"
        },

        
        
        }
});

// Load the main app module to start the app
requirejs(["app"]);

</script>



</body>
</html>
define(["jquery",'ladda','spin'], function($,ladda) {
    //the jquery.alpha.js and jquery.beta.js plugins have been loaded.
    $(function() {
      console.log("$: " + typeof $);
      console.log("ladda: " + typeof Ladda);
      console.log("spin: " + typeof Spinner);
      
      Ladda.bind($('button')[0]); //don't work ????????????
      //return;
      //Ladda.create('.ladda-button');
      var l = Ladda.create($('button')[1]);
     
    l.start();

// Will display a progress bar for 50% of the button width
l.setProgress( 5 );

// Stop loading
l.stop();

// Toggle between loading/not loading states
l.toggle();

// Check the current state
l.isLoading();
     
     
    });
});
/*!
 * Ladda
 * http://lab.hakim.se/ladda
 * MIT licensed
 *
 * Copyright (C) 2013 Hakim El Hattab, http://hakim.se
 */


/*************************************
 * BUTTON BASE
 */

.ladda-button {
  position: relative;
  background: none;
	border: 0;
	padding: 0.8em 1em;
	font-size: 1.3em;
	cursor: pointer;
	overflow: hidden;

	-webkit-appearance: none;
	-webkit-font-smoothing: antialiased;
	-webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}
	.ladda-button[data-loading] {
		cursor: default;
	}

/* Green button */
.ladda-button.green {
	background: #2aca76;
	color: #fff;
	border-radius: 2px;
	border: 1px solid transparent;
}
	.ladda-button.green:hover {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #2fe688;
	}
	.ladda-button.green[data-loading] {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #999;
	}

/* Blue button */
.ladda-button.blue {
	background: #53b5e6;
	color: #fff;
	border-radius: 2px;
	border: 1px solid transparent;
}
	.ladda-button.blue:hover {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #58c2f8;
	}
	.ladda-button.blue[data-loading] {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #999;
	}

/* Red button */
.ladda-button.red {
	background: #ea8557;
	color: #fff;
	border-radius: 2px;
	border: 1px solid transparent;
}
	.ladda-button.red:hover {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #ffa96c;
	}
	.ladda-button.red[data-loading] {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #999;
	}

/* Purple button */
.ladda-button.purple {
	background: #9973C2;
	color: #fff;
	border-radius: 2px;
	border: 1px solid transparent;
}
	.ladda-button.purple:hover {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #b084df;
	}
	.ladda-button.purple[data-loading] {
		border-color: rgba( 0, 0, 0, 0.07 );
		background-color: #999;
	}


/* Spinner animation */
.ladda-button .ladda-spinner {
	position: absolute;
	z-index: 2;
	display: inline-block;
	width: 32px;
	height: 32px;
	top: 50%;
	margin-top: -16px;
	opacity: 0;
}

/* Button label */
.ladda-button .ladda-label {
	position: relative;
	z-index: 3;
}

/* Progress bar */
.ladda-button .ladda-progress {
	position: absolute;
	width: 0;
	height: 100%;
	left: 0;
	top: 0;
	background: rgba( 0, 0, 0, 0.2 );

	visibility: hidden;
	opacity: 0;

	-webkit-transition: 0.1s linear all;
	   -moz-transition: 0.1s linear all;
	    -ms-transition: 0.1s linear all;
	        transition: 0.1s linear all;
}
	.ladda-button[data-loading] .ladda-progress {
		opacity: 1;
		visibility: visible;
	}


/*************************************
 * EASING
 */

.ladda-button,
.ladda-button .ladda-spinner,
.ladda-button .ladda-label {
	-webkit-transition: 0.3s cubic-bezier(0.175, 0.885, 0.320, 1.275) all;
	   -moz-transition: 0.3s cubic-bezier(0.175, 0.885, 0.320, 1.275) all;
	    -ms-transition: 0.3s cubic-bezier(0.175, 0.885, 0.320, 1.275) all;
	        transition: 0.3s cubic-bezier(0.175, 0.885, 0.320, 1.275) all;
}

.ladda-button.zoom-in,
.ladda-button.zoom-in .ladda-spinner,
.ladda-button.zoom-in .ladda-label,
.ladda-button.zoom-out,
.ladda-button.zoom-out .ladda-spinner,
.ladda-button.zoom-out .ladda-label {
	-webkit-transition: 0.3s ease all;
	   -moz-transition: 0.3s ease all;
	    -ms-transition: 0.3s ease all;
	        transition: 0.3s ease all;
}


/*************************************
 * EXPAND LEFT
 */

.ladda-button.expand-right .ladda-spinner {
	right: 0.8em;
}

.ladda-button.expand-right[data-loading] {
	padding-right: 56px;
}
	.ladda-button.expand-right[data-loading] .ladda-spinner {
		opacity: 1;
	}


/*************************************
 * EXPAND RIGHT
 */

.ladda-button.expand-left .ladda-spinner {
	left: 0.8em;
}

.ladda-button.expand-left[data-loading] {
	padding-left: 56px;
}
	.ladda-button.expand-left[data-loading] .ladda-spinner {
		opacity: 1;
	}


/*************************************
 * EXPAND UP
 */

.ladda-button.expand-up {
	overflow: hidden;
}
	.ladda-button.expand-up .ladda-spinner {
		top: -32px;
		left: 50%;
		margin-left: -16px;
	}

.ladda-button.expand-up[data-loading] {
	padding-top: 3em;
}
	.ladda-button.expand-up[data-loading] .ladda-spinner {
		opacity: 1;
		top: 0.8em;
		margin-top: 0;
	}


/*************************************
 * EXPAND DOWN
 */

.ladda-button.expand-down {
	overflow: hidden;
}
	.ladda-button.expand-down .ladda-spinner {
		top: 3.3em;
		left: 50%;
		margin-left: -16px;
	}

.ladda-button.expand-down[data-loading] {
	padding-bottom: 3em;
}
	.ladda-button.expand-down[data-loading] .ladda-spinner {
		opacity: 1;
	}


/*************************************
 * SLIDE LEFT
 */
.ladda-button.slide-left {
	overflow: hidden;
}
	.ladda-button.slide-left .ladda-label {
		position: relative;
	}
	.ladda-button.slide-left .ladda-spinner {
		left: 100%;
		margin-left: -16px;
	}

.ladda-button.slide-left[data-loading] .ladda-label {
	opacity: 0;
	left: -100%;
}
.ladda-button.slide-left[data-loading] .ladda-spinner {
	opacity: 1;
	left: 50%;
}


/*************************************
 * SLIDE RIGHT
 */
.ladda-button.slide-right {
	overflow: hidden;
}
	.ladda-button.slide-right .ladda-label {
		position: relative;
	}
	.ladda-button.slide-right .ladda-spinner {
		right: 100%;
		margin-left: -16px;
	}

.ladda-button.slide-right[data-loading] .ladda-label {
	opacity: 0;
	left: 100%;
}
.ladda-button.slide-right[data-loading] .ladda-spinner {
	opacity: 1;
	left: 50%;
}


/*************************************
 * SLIDE UP
 */
.ladda-button.slide-up {
	overflow: hidden;
}
	.ladda-button.slide-up .ladda-label {
		position: relative;
	}
	.ladda-button.slide-up .ladda-spinner {
		left: 50%;
		margin-left: -16px;
		margin-top: 1em;
	}

.ladda-button.slide-up[data-loading] .ladda-label {
	opacity: 0;
	top: -1em;
}
.ladda-button.slide-up[data-loading] .ladda-spinner {
	opacity: 1;
	margin-top: -16px;
}


/*************************************
 * SLIDE DOWN
 */
.ladda-button.slide-down {
	overflow: hidden;
}
	.ladda-button.slide-down .ladda-label {
		position: relative;
	}
	.ladda-button.slide-down .ladda-spinner {
		left: 50%;
		margin-left: -16px;
		margin-top: -2em;
	}

.ladda-button.slide-down[data-loading] .ladda-label {
	opacity: 0;
	top: 1em;
}
.ladda-button.slide-down[data-loading] .ladda-spinner {
	opacity: 1;
	margin-top: -16px;
}


/*************************************
 * ZOOM-OUT
 */

.ladda-button.zoom-out {
	overflow: hidden;
}
	.ladda-button.zoom-out .ladda-spinner {
		left: 50%;
		margin-left: -16px;

		-webkit-transform: scale( 2.5 );
		   -moz-transform: scale( 2.5 );
		    -ms-transform: scale( 2.5 );
		        transform: scale( 2.5 );
	}
	.ladda-button.zoom-out .ladda-label {
		position: relative;
		display: inline-block;
	}

.ladda-button.zoom-out[data-loading] .ladda-label {
	opacity: 0;

	-webkit-transform: scale( 0.5 );
	   -moz-transform: scale( 0.5 );
	    -ms-transform: scale( 0.5 );
	        transform: scale( 0.5 );
}
.ladda-button.zoom-out[data-loading] .ladda-spinner {
	opacity: 1;

	-webkit-transform: none;
	   -moz-transform: none;
	    -ms-transform: none;
	        transform: none;
}


/*************************************
 * ZOOM-IN
 */

.ladda-button.zoom-in {
	overflow: hidden;
}
	.ladda-button.zoom-in .ladda-spinner {
		left: 50%;
		margin-left: -16px;

		-webkit-transform: scale( 0.2 );
		   -moz-transform: scale( 0.2 );
		    -ms-transform: scale( 0.2 );
		        transform: scale( 0.2 );
	}
	.ladda-button.zoom-in .ladda-label {
		position: relative;
		display: inline-block;
	}

.ladda-button.zoom-in[data-loading] .ladda-label {
	opacity: 0;

	-webkit-transform: scale( 2.2 );
	   -moz-transform: scale( 2.2 );
	    -ms-transform: scale( 2.2 );
	        transform: scale( 2.2 );
}
.ladda-button.zoom-in[data-loading] .ladda-spinner {
	opacity: 1;

	-webkit-transform: none;
	   -moz-transform: none;
	    -ms-transform: none;
	        transform: none;
}


/*************************************
 * CONTRACt
 */

.ladda-button.contract {
	overflow: hidden;
	width: 100px;
}
	.ladda-button.contract .ladda-spinner {
		left: 50%;
		margin-left: -16px;
	}

.ladda-button.contract[data-loading] {
	border-radius: 50%;
	width: 52px;
}
	.ladda-button.contract[data-loading] .ladda-label {
		opacity: 0;
	}
	.ladda-button.contract[data-loading] .ladda-spinner {
		opacity: 1;
	}



/*************************************
 * OVERLAY
 */

.ladda-button.contract-overlay {
	overflow: hidden;
	width: 100px;

	box-shadow: 0px 0px 0px 3000px rgba(0,0,0,0);
}
	.ladda-button.contract-overlay .ladda-spinner {
		left: 50%;
		margin-left: -16px;
	}

.ladda-button.contract-overlay[data-loading] {
	border-radius: 50%;
	width: 52px;

	/*outline: 10000px solid rgba( 0, 0, 0, 0.5 );*/
	box-shadow: 0px 0px 0px 3000px rgba(0,0,0,0.8);
}
	.ladda-button.contract-overlay[data-loading] .ladda-label {
		opacity: 0;
	}
	.ladda-button.contract-overlay[data-loading] .ladda-spinner {
		opacity: 1;
	}











/*!
 * Ladda 0.3.0
 * http://lab.hakim.se/ladda
 * MIT licensed
 *
 * Copyright (C) 2013 Hakim El Hattab, http://hakim.se
 */
window.Ladda =(function() {

  var ALL_INSTANCES = [];

  /**
	 * Creates a new instance of Ladda which wraps the 
	 * target button element.
	 *
	 * @return An API object that can be used to control
	 * the loading animation state.
	 */
	function create( button ) {

		if( typeof button === 'undefined' ) {
			throw "Button target must be defined.";
		}

		// Create the spinner
		  var spinner = new Spinner( {
			color: '#fff',
			lines: 12,
			radius: 8,
			length: 5,
			width: 3,
			zIndex: 'initial',
			top: 'auto',
			left: 'auto',
			className: ''
		} );

		// Wrapper element for the spinner
		var spinnerWrapper = document.createElement( 'span' );
		spinnerWrapper.className = 'ladda-spinner';
		button.appendChild( spinnerWrapper );

		// Timeout used to delay stopping of the spin animation
		var spinnerTimeout;

		var instance = {
			

			start: function() {

				button.setAttribute( 'disabled', '' );
				button.setAttribute( 'data-loading', '' );

				clearTimeout( spinnerTimeout );
				spinner.spin( spinnerWrapper );

				this.setProgress( 0 );

				return this; // chain

			},

			stop: function() {

				button.removeAttribute( 'disabled', '' );
				button.removeAttribute( 'data-loading' );

				// Kill the animation after a delay to make sure it
				// runs for the duration of the button transition
				clearTimeout( spinnerTimeout );
				spinnerTimeout = setTimeout( function() { spinner.stop(); }, 1000 );

				return this; // chain

			},

			toggle: function() {

				if( this.isLoading() ) {
					this.stop();
				}
				else {
					this.start();
				}

				return this; // chain

			},

			setProgress: function( progress ) {

				var progressElement = button.querySelector( '.ladda-progress' );

				// Remove the progress bar if we're at 0 progress
				if( progress === 0 && progressElement && progressElement.parentNode ) {
					progressElement.parentNode.removeChild( progressElement );
				}
				else {
					if( !progressElement ) {
						progressElement = document.createElement( 'div' );
						progressElement.className = 'ladda-progress';
						button.appendChild( progressElement );
					}

					progressElement.style.width = ( ( progress || 0 ) * button.offsetWidth ) + 'px';
				}

			},

			isLoading: function() {

				return button.hasAttribute( 'data-loading' );

			}

		};

		ALL_INSTANCES.push( instance );

		return instance;

	}

	/**
	 * Binds the target buttons to automatically enter the 
	 * loading state when clicked.
	 *
	 * @param target Either an HTML element or a CSS selector.
	 * @param options 
	 *          - timeout Number of milliseconds to wait before
	 *            automatically cancelling the animation.
	 */
	function bind( target, options ) {

		options = options || {};

		var targets = [];

		if( typeof target === 'string' ) {
			targets = [].slice.call( document.querySelectorAll( target ) );
		}
		else if( typeof target === 'object' && typeof target.nodeName === 'string' ) {
			targets = [ targets ];
		}

		for( var i = 0, len = targets.length; i < len; i++ ) {

			(function() {
				var element = targets[i];

				// Make sure we're working with a DOM element
				if( typeof element.addEventListener === 'function' ) {
					var instance = Ladda.create( element );
					var timeout = -1;

					element.addEventListener( 'click', function() {
						
						instance.start();

						// Set a loading timeout if one is specified
						if( typeof options.timeout === 'number' ) {
							clearTimeout( timeout );
							timeout = setTimeout( instance.stop, options.timeout );
						}

						// Invoke callbacks
						if( typeof options.callback === 'function' ) {
							options.callback.apply( null, [ instance ] );
						}

					}, false );
				}
			})();

		}

	}

	/**
	 * Stops ALL current loading animations.
	 */
	function stopAll() {

		for( var i = 0, len = ALL_INSTANCES.length; i < len; i++ ) {
			ALL_INSTANCES[i].stop();
		}

	}

	// Public API
	return {

		bind: bind,
		create: create,
		stopAll: stopAll

	}

})();

//fgnass.github.com/spin.js#v1.3

/**
 * Copyright (c) 2011-2013 Felix Gnass
 * Licensed under the MIT license
 */
window.Spinner =(function() {
  "use strict";

  var prefixes = ['webkit', 'Moz', 'ms', 'O'] /* Vendor prefixes */
    , animations = {} /* Animation rules keyed by their name */
    , useCssAnimations /* Whether to use CSS animations or setTimeout */

  /**
   * 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')
      , 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', {type : 'text/css'})
    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('-')
      , start = 0.01 + i/lines * 100
      , z = Math.max(1 - (1-alpha) / trail * (100-start), alpha)
      , prefix = useCssAnimations.substring(0, useCssAnimations.indexOf('Animation')).toLowerCase()
      , 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 + '}' +
        '}', sheet.cssRules.length)

      animations[name] = 1
    }

    return name
  }

  /**
   * Tries various vendor prefixes and returns the first supported property.
   */
  function vendor(el, prop) {
    var s = el.style
      , pp
      , 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
  }

  // Built-in defaults

  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
    rotate: 0,            // Rotation offset
    corners: 1,           // Roundness (0..1)
    color: '#000',        // #rgb or #rrggbb
    direction: 1,         // 1: clockwise, -1: counterclockwise
    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
    position: 'relative'  // element position
  }

  /** The constructor */
  function Spinner(o) {
    
    if (typeof this == 'undefined') return new Spinner(o)
    this.opts = merge(o || {}, Spinner.defaults, defaults)
  }

  // Global defaults that override the built-ins:
  Spinner.defaults = {}

  merge(Spinner.prototype, {

    /**
     * Adds the spinner to the given target element. If this instance is already
     * spinning, it is automatically removed from its previous target b calling
     * stop() internally.
     */
    spin: function(target) {
      this.stop()

      var self = this
        , o = self.opts
        , el = self.el = css(createEl(0, {className: o.className}), {position: o.position, width: 0, zIndex: o.zIndex})
        , mid = o.radius+o.length+o.width
        , ep // element position
        , 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) : parseInt(o.left, 10) + mid) + 'px',
          top: (o.top == 'auto' ? tp.y-ep.y + (target.offsetHeight >> 1) : parseInt(o.top, 10) + mid)  + 'px'
        })
      }

      el.setAttribute('role', 'progressbar')
      self.lines(el, self.opts)

      if (!useCssAnimations) {
        // No CSS animation support, use setTimeout() instead
        var i = 0
          , start = (o.lines - 1) * (1 - o.direction) / 2
          , alpha
          , fps = o.fps
          , f = fps/o.speed
          , ostep = (1-o.opacity) / (f*o.trail / 100)
          , astep = f/o.lines

        ;(function anim() {
          i++;
          for (var j = 0; j < o.lines; j++) {
            alpha = Math.max(1 - (i + (o.lines - j) * astep) % f * ostep, o.opacity)

            self.opacity(el, j * o.direction + start, alpha, o)
          }
          self.timeout = self.el && setTimeout(anim, ~~(1000/fps))
        })()
      }
     
      return self
    },

    /**
     * Stops and removes the Spinner.
     */
    stop: function() {
      var el = this.el
      if (el) {
        clearTimeout(this.timeout)
        if (el.parentNode) el.parentNode.removeChild(el)
        this.el = undefined
      }
      return this
    },

    /**
     * Internal method that draws the individual lines. Will be overwritten
     * in VML fallback mode below.
     */
    lines: function(el, o) {
      var i = 0
        , start = (o.lines - 1) * (1 - o.direction) / 2
        , 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+o.rotate) + 'deg) translate(' + o.radius+'px' +',0)',
          borderRadius: (o.corners * 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, start + i * o.direction, 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
    },

    /**
     * Internal method that adjusts the opacity of a single line.
     * Will be overwritten in VML fallback mode below.
     */
    opacity: function(el, i, val) {
      if (i < el.childNodes.length) el.childNodes[i].style.opacity = val
    }

  })


  function initVML() {

    /* Utility function to create a VML tag */
    function vml(tag, attr) {
      return createEl('<' + tag + ' xmlns="urn:schemas-microsoft.com:vml" class="spin-vml">', attr)
    }

    // No CSS transforms but VML support, add a CSS rule for VML elements:
    sheet.addRule('.spin-vml', 'behavior:url(#default#VML)')

    Spinner.prototype.lines = function(el, o) {
      var r = o.length+o.width
        , s = 2*r

      function grp() {
        return css(
          vml('group', {
            coordsize: s + ' ' + s,
            coordorigin: -r + ' ' + -r
          }),
          { width: s, height: s }
        )
      }

      var margin = -(o.width+o.length)*2 + 'px'
        , g = css(grp(), {position: 'absolute', top: margin, left: margin})
        , i

      function seg(i, dx, filter) {
        ins(g,
          ins(css(grp(), {rotation: 360 / o.lines * i + 'deg', left: ~~dx}),
            ins(css(vml('roundrect', {arcsize: o.corners}), {
                width: r,
                height: o.width,
                left: o.radius,
                top: -o.width>>1,
                filter: filter
              }),
              vml('fill', {color: o.color, opacity: o.opacity}),
              vml('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
      }
    }
  }

  var probe = css(createEl('group'), {behavior: 'url(#default#VML)'})

  if (!vendor(probe, 'transform') && probe.adj) initVML()
  else useCssAnimations = vendor(probe, 'animation')

  return Spinner

})();