JSFiddle - React, Tailwind, and code Playground

HTML

<div style="padding: 30px;">
    <object width="420" height="315">
        <param name="movie" value="http://www.youtube.com/v/dQw4w9WgXcQ?version=3&amp;hl=en_US"></param>
        <param name="allowFullScreen" value="true"></param>
        <param name="allowscriptaccess" value="always"></param>
        <embed src="http://www.youtube.com/v/dQw4w9WgXcQ?version=3&amp;hl=en_US" type="application/x-shockwave-flash" width="420" height="315" allowscriptaccess="always" allowfullscreen="true"></embed>
    </object>
</div>
<div id="overlay" style="height: 30px; width: 30px; background: #f00;"></div>

JavaScript

$( "#overlay" ).position({
    my: "left top",
    at: "left top",
    of: $( "embed" )
});