The CSS:
<style>
.embed-container {
position: relative;
padding-bottom: 56.25%;
height: 0;
overflow: hidden;
max-width: 100%;
}
.embed-container iframe,
.embed-container object,
.embed-container embed {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
</style>
The HTML:
<div class='embed-container'>
<iframe width='640' height='360' src='http://cache.vevo.com/assets/html/embed.html?video=QMGR31536628&autoplay=0' frameborder='0' allowfullscreen></iframe>
</div>
You can drop the whole thing into the DOM using this:
<style>.embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }</style><div class='embed-container'><iframe width='640' height='360' src='http://cache.vevo.com/assets/html/embed.html?video=QMGR31536628&autoplay=0' frameborder='0' allowfullscreen></iframe></div>