Link straight from youtube

<iframe src="https://www.youtube.com/embed/n6p6yGpvc7M" width="560" height="315" frameborder="0" allowfullscreen="allowfullscreen"></iframe>

&nbsp;

test 2

<style>
.embed-container {<br />
   position: relative;<br />
   padding-bottom: 39.25%;<br />
   height: 0;<br />
   overflow: visible;<br />
   max-width: 100%;<br />
   width: 70%;<br />
   margin: 0 auto;<br />
}<br />
.embed-container iframe,<br />
.embed-container object,<br />
.embed-container embed {<br />
   position: absolute;<br />
   top: 0;<br />
   left: 0;<br />
   width: 100%;<br />
   height: 100%;<br />
}<br />
</style>
<div class="embed-container"><iframe src="https://www.youtube.com/embed/n6p6yGpvc7M" width="300" height="150" frameborder="0" allowfullscreen="allowfullscreen"></iframe></div>