According to Google, the best way to embed is to use iframes:
Best practice: IFrame embeds are the recommended method for embedding a YouTube player because the IFrame will select the appropriate player based on the client's capabilities and available YouTube file formats.
That would look like this:
<iframe width="420" height="315" src="//www.youtube.com/embed/jRXQsQKGqIU" frameborder="0" allowfullscreen></iframe>
However, if you wish to use the Object tag, here's a working example:
<object width="640" height="390">
<param name="movie"
value="https://www.youtube.com/v/jRXQsQKGqIU?version=3&autoplay=1"></param>
<param name="allowScriptAccess" value="always"></param>
<embed src="https://www.youtube.com/v/M7lc1UVf-VE?version=3&autoplay=1"
type="application/x-shockwave-flash"
allowscriptaccess="always"
width="640" height="390"></embed>
</object>
Working JS Fiddle: http://jsfiddle.net/RAZC4/2/