I've managed to do a Iframe that shows only certain part of the page with this code:
<div id="divContainer" style="display: block; margin-left: auto; margin-right: auto;">
<div id="frameContainer" style="overflow:hidden;">
<iframe src="http://www.cofm.es/informacion-corporativa/buscador-farmacias" scrolling="no" style="width: 1000px; height: 750px; margin-top: -330px; margin-left: -250px;" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe><br />
</div>
Source: iframe to Only Show a Certain Part of the Page
Now what I'm trying to do is to make the Iframe show on the 100% width on the screen. I've been able to do this with images with this code:
<img style="width: 100%; display: block; margin-left: auto; margin-right: auto; " src="http://i.ytimg.com/vi/ROv863DuJu4/maxresdefault.jpg" />
I'm trying to make the iframe adapt to the screen size like the image does.