How can I make the YouTube player scale to the width of the page but also keep the aspect ratio?

Question

I have a YouTube video I want to put on my web page.

I want to scale the video to fit to a percent of the users browser but also to keep the aspect ratio.

I have tried this:

<iframe width="87%" height="315" src="http://www.youtube-nocookie.com/embed/dU6OLsnmz7o" frameborder="0" allowfullscreen></iframe>

But that does only make the player wider, not higher.

Does I have to resort to JavaScript (or non-standard CSS)?

Answer 1

What i believe to be the best CSS solution.

.auto-resizable-iframe {
  max-width: 420px;
  margin: 0px auto;
}

.auto-resizable-iframe > div {
  position: relative;
  padding-bottom: 75%;
  height: 0px;
}

.auto-resizable-iframe iframe {
  position: absolute;
  top: 0px;
  left: 0px;
  width: 100%;
  height: 100%;
}

<div class="auto-resizable-iframe">
  <div>
    <iframe frameborder="0" allowfullscreen="" src="http://www.youtube.com/embed/_OBlgSz8sSM"></iframe>
  </div>
</div>

Demo http://jsfiddle.net/JBhp2/