I want to do something like this:
<li style="hover:background-color:#006db9;">
But it wont work. Is this possible to do in some way, or do I have to write the css in the head or external css-document?
It is not possible with inline styles, but the (in)famous onmouseover / onmouseout event handler can do the same thing.
<li onmouseover="this.style.backgroundColor='#006db9'" onmouseout="this.style.backgroundColor=''">
Caveat: CSS definitions with hyphens have to be translated to Javascript using camelCase, like (css)background-color = (javascript)backgroundColor
This is not possible using the style attribute. You'll have to use CSS, either in the document itself or in an external file.
li:hover { background-color:#006db9; }
If that's not an option then you'll have to resort to JavaScript.
Instead of just having the <li>, you can nest it in an anchors tag <a href="#" class="hoverable"> and then put this styling at the top of the file or in an external CSS file:
a.hoverable:hover{background-color:#006db9}
Or you can just use Javascript to avoid using the anchor tag.
I'd recommend JQuery.