I know that h1 and h2 content should be on top of the code for a better SEO and left menu should be under that and than positioned with css. But what is about a top menu and header images. For example if I use jquery for Auto rotation enabled images inside header and under that I put the top menu. Should also that be coded after h1,h2 tags and than positioned to above with css? Thank you
The source code order won't play that much of a role unless you have a really large menu. Also, when using CSS, there is no "left" or "right" as far as location goes, just higher or lower (in the source code). Personally what I do is take the header, include a skip link to the main content and put the logo in there. If I'm going to have a randomly rotating background image, I'll assign a dynamic class to the header (such as <div class="sunset" id="header"><img src="/images/logo.png" alt="(Site Name)" title=""></div> for example; note that (Site Name) is just a placeholder). I'll then put the main menu under that, followed by the search form and/or breadcrumb menu, and then proceed right to the content. If I'm dealing with a sectional menu, I'll have that come after the content. I can post an example, if you like.
I tend to use background images in the header. One can rotate these too, if you know your css and a server side scripting language.
Or JavaScript. Just add the class dynamically on the client-side and then let the browser look up the generated class in the stylesheet. (But a server-side programming language is better.)