I've added some div boxes, but once I save they disappear ?

Hi

I’m using, or atleast want to use:

<div class="pdf_outside">
<div class="pdf_left"><img src="pdf.jpg" /></div>
<div class="pdf_right">Christmas Menu 2011</div>
</div>

within one of the pages of my WP website, to create 2 horizontal boxes.

I’ve copied and pasted this into the page (html view) and saved it, I’ve also changed the style.css file.

As soon as I’ve done that its then disappeared from the code and the page ?

Am I missing something ?

:0)

[Please post code snippets between backticks or use the code button.]