Javascript – Google Plus or Facebook Style Image Popup Viewer?

Use document.activeElement, it is supported in all major browsers.

Previously, if you were trying to find out what form field has focus, you could not. To emulate detection within older browsers, add a "focus" event handler to all fields and record the last-focused field in a variable. Add a "blur" handler to clear the variable upon a blur event for the last-focused field.

If you need to remove the activeElement you can use blur; document.activeElement.blur(). It will change the activeElement to body.

Related links:

• activeElement Browser Compatibility
• jQuery alternative for document.activeElement

1. You'll want jQuery. jQuery.com
2. Jquery has tons of useful plugins: jquery plugins page

3. Start searching! Here's a good one i found searching for "image galley"

4. Enjoy. Jquery is your friend. Of course this post is biased. So, to give credits to others, you can also look into mootools, YUI, prototype, scriptaculous, etc.