html
<header class="page-header" role="banner">
<h1>hover_img_caption</h1>
</header>
<div class="page-main" role="main">
<div id="images">
<h2>IMAGES</h2>
<div class="inner clearfix">
<p>
<img src="https://i.pinimg.com.jpg">
<strong>caption</strong>
<span></span>
</p>
<p>
<img src="https://i.pinimg.com.jpg">
<strong>caption</strong>
<span></span>
</p>
<p>
<img src="https://i.pinimg.com.jpg">
<strong>caption</strong>
<span></span>
</p>
</div>
</div>
</div>
공백 o = find
공백 x = filter
#images p span { } -> $image.find('span')
#images p.strong { } -> $image.filter('strong')
span,strong { } -> $image.find('span, strong')
#images p:nth-child(2) -> $image.filter(':nth-child(2)')
var $duration = 300,
$image = $('images p');
$image.filter(':nth-child(1)').mouseover(function(){
$(this).find('span, strong').stop().animate({opacity:1},$duration)
})
.mouseout(function(){
$(this).find('span, strong').stop().animate({opacity:0},$duration)
})