centre{source}

The web continues to impress me when I stumble across things that are relatively simple, yet done in such an elegant manner I can't help but notice. This was the case when I discovered the Javascript overlay techniques of Lightbox, Greybox, and Thickbox.

Lightbox
Lightbox provides functionality to overlay images (with effects) onto your website - without using Flash or other plugins. It is perfect for creating a beautiful image gallery, while still maintaining easy control over your images! Don't take my word for it, see for yourself: Lightbox JS v2.0

Note: In the same session, I also found a 'Lite' version for anyone that wants the same functionality, but with less code (and presumably resources). It is called Litebox 1.0

Litebox is a modified version of Lightbox v2.0 created with one thing in mind, size reduction. Litebox utilizes the 3kb javascript library moo.fx in association with prototype.lite, giving us the basic tools we need to make this work and you the ability to expand.

Greybox
Greybox provides functionality to overlay HTML pages on your website - it describes itself as a "A pop-up window that doesn't suck". Greybox is very useful for providing visitors with additional information, a 'focus area' to input data, etc. Here is a demo page that shows the functionality of Greybox. Again, the smooth screen effects that are NOT using flash. SEO and Maintenance are still preserved (Flash experts, don't flame me).

Thickbox
Last but not least, we have Thickbox. Thickbox combines both Lightbox and Greybox functionality, and still remains light weight - less than 50KB! It was actually the creator's blog that introduced me to all three examples (Thank you Cody Lindley). You can view the demo to see the Thickbox in action - and notice that it can display overlays for the following extensions: .jpg .jpeg .png .gif .html .htm .cfm .php .asp .aspx .jsp .jst .rb .txt. It also supports AJAX/AXAH calls!
*Note: Inexperienced Javascript users may still consider Lightbox over Thickbox since it has some nice effects that Thickbox does not (example: Previous/Next tabs & hot keys)