Here is a demo showing the usage of
responsive-embed class from Zurb Foundation. It keeps the proportion of the embed video player, resulting in a much better looking in various screen sizes. Additional
widescreen class or
panorama class allows different ratio.
<div class="responsive-embed"> <iframe width="420" height="315" src="https://www.youtube.com/embed/mM5_T-F1Yn4" frameborder="0" allowfullscreen></iframe> </div>