HTML Fullscreen iFrame


I am trying to add an iFrame to a page but I think the theme is stopping if from showing the full width of the page.

This is the code I am using:

body, html{<br />
		height:100%;<br />
		width:100%;<br />
		overflow-y: hidden;<br />
}<br />

<iframe style=""height: 100%;" src="" width="300" height="150"></iframe>

Is the theme interfering or am I using the wrong code?