It's a javascript script, it has to be include in a script tag
THE SCRIPT NODE MUST CONTAIN THE ID SPECIFIED IN THE SAMPLE BELOW
Click here to access to test page
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
<title>Default test page</title>
<script type="text/javascript">
DYDU_QUALIFICATION_MODE = true;
</script>
<script id="dyduchatbox" src="assembly.min.js"></script>
</head>
<body>
<div class="dydu-background"></div>
<!-- html sample -->
</body>
</html>