2011 Interview season! Here are some  questions I ran into:

 

CSS:

the difference between “visibility=hidden” and “display=none”

visibility: hidden hides the element, but it still takes up space in the layout.
display: none removes the element completely from the document. It does not take up any space, even though the HTML for it is still in the source code.
http://webdesign.about.com/od/examples/l/blfaqhidden.htm

 

Javascript:

Explain Closures

How to define a class

 

Basic DB:

The pros and cons of normalization

 

Caching:

If you want to cache a dynamic page, how do you deal with the dynamic content

 

Other:

Amazon Elastic Compute Cloud (Amazon EC2)