How to add div inside other div in gallery script using jQuery?

I want to add a <div> inside a <div class="ad-image"> - How can it be done?

Gallery script is here: http://coffeescripter.com/code/ad-gallery/

This is the way I created <div class="开发者_StackOverflow社区ad-image">

var img_container = $(document.createElement('div')).addClass('ad-image');

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var img_container = $(document.createElement('div')).addClass('ad-image'),
    new_div = $("<div></div>");

img_container.append(new_div);

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You can do it by

$(".ad-image").append("<div>New div here</div>")

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$('<div class="ad-image" />').appendTo($('div'));

Working jsfiddle: JsFiddle demo