Responsive iFrames with jQuery

responsive-iframes.html

<!-- All you need is a defined width & height -->
<iframe frameborder="0" height="426" src="http://www.slideshare.net/slideshow/embed_code/9812085?rel=0" width="510"></iframe>

responsive-iframes.js

function adjustIframes()
{
  $('iframe').each(function(){
  	
	 var
	 $this = $(this),
	 w = $this.attr('width'),
	 h = $this.attr('height'),
	 proportion = h / w;
    	
    	var new_w=$this.parent().width();
    	var new_h=Math.round( new_w * proportion );
    	
        $this.height(new_h);
        $this.width(new_w);
   
  });
}

$(window).on('resize load',adjustIframes);

Removed the CSS to make the JavaScript self-contained.