I want to run<div id="ab_c"></div> it via JavaScript HOW???

I want to run<div id="ab_c"></div> it via JavaScript HOW???



i have 

<head>
<meta charset="utf-8"/>
<title>Varis Creative Templtate</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=0, minimum-scale=1.0, maximum-scale=1.0">

<script src="main.js"></script>


$(document).ready(function() {
jg_gallery_init("#ab_c");
});
</head>

<body>
<div id="ab_c">
</div>
</body>

I want to run<div id="ab_c"></div>  it via JavaScript  HOW???
BODY EMPTY.