<section class="content_accordion section">
				<header class="section_index">
					<h2>accordion</h2>
				</header>
				<div class="section_content">
					<dl class="content_accordion_child" data-accordion="open">
						<dt class="content_accordion_child_index">
							見出し1
							<span class="content_accordion_child_indexCap close">close</span>
							<span class="content_accordion_child_indexCap open">open</span>													
						</dt>
						<dd class="content_accordion_child_content" >
							 <p>アコーディオン1のコンテンツアコーディオン1のコンテンツ<br>アコーディオン1のコンテンツ</p>
						</dd>
					</dl>
					<dl class="content_accordion_child close" data-accordion="close">
						<dt class="content_accordion_child_index">
							見出し2
							<span class="content_accordion_child_indexCap close">close</span>
							<span class="content_accordion_child_indexCap open">open</span>													
						</dt>
						<dd class="content_accordion_child_content" >
							 <p>アコーディオン2のコンテンツアコーディオン2のコンテンツ<br>アコーディオン2のコンテンツ</p>
						</dd>
					</dl>
					<dl class="content_accordion_child close" data-accordion="close">
						<dt class="content_accordion_child_index">
							見出し3
							<span class="content_accordion_child_indexCap close">close</span>
							<span class="content_accordion_child_indexCap open">open</span>							
						</dt>
						<dd class="content_accordion_child_content" >
							 <p>アコーディオン3のコンテンツアコーディオン3のコンテンツ<br>アコーディオン3のコンテンツ</p>
						</dd>
					</dl>
				</div>
			</section>

	<script type="text/javascript" src="http://satohmsys.info/files/demo/tweenmax/site/js/tweenmax/minified/TweenMax.min.js"></script>

var getByClass = function( cls, num ){
	if( typeof num == "number" ){
		classCollection = document.getElementsByClassName( cls )[num];
	} else {
		classCollection = document.getElementsByClassName( cls );
		classCollection.length == 1 ? classCollection = classCollection[0] : '';

	}
	return classCollection;
};

$accordion = getByClass( 'content_accordion_child' ),
$accordion_tab = getByClass( 'content_accordion_child_index' ),
$TimelineMax = new TimelineMax();


/**
* アコーディオン
*/

Array.prototype.forEach.call( $accordion, function( e, index ){
	var $index =  e.getElementsByClassName( 'content_accordion_child_index' );

	$index[0].addEventListener( 'click', function( e ){
		var $text = e.target;
		
		if( /indexCap/.test( $text.className ) ){
			$parent = $text.parentNode,
			$dd = $parent.nextElementSibling,
			$dtHeight = $parent.clientHeight;
		} else {
			$dd = $text.nextElementSibling,
			$dtHeight = $text.clientHeight;
		}
		$dl = $dd.parentNode,
		$status = $dl.getAttribute('data-accordion');

		//open時＝閉じる
		if( $status == 'open' ){		
			$TimelineMax.fromTo( $dd, 0.5, {
				overflow: 'hidden',
			},
			{
				height: 0,
				display: 'none',
				ease:Back.easeIn,
				onComplete: function( ){
					$dl.setAttribute( 'data-accordion', 'close' );
				}
			});
		} else {
			//close時＝開く
			
			$TimelineMax.fromTo( $dd, 1, {
				display: 'block',
				overflow: 'hidden'
			},
			{
				height: '80%',
				delay: 0.5,
				ease:Bounce.easeOut,
				onComplete: function(){
					$dl.setAttribute( 'data-accordion', 'open' );
				}
			});		
		}
		
	} );
} );