How to make transparent background of a gif animation?

I have a gif animation with white background.
Is there a simple way (e.g., free or shareware application) to remove this white background and make it transparent?

Solution 1:

You can just use an online editing service like gifmagic.com

Solution 2:

You can use the Online Image Editor tool.

You can find this option in:

Wizards --> Transparency.

Working fine!

Solution 3:

The best way to create a Photoshop script Alt+F9 would be:

1. Select all
2. Select color
3. Remove this color
4. Unselect all
5. Activate next frame
6. Choose next video step

Then run this script from the first frame of opened animated GIF-file. For 100 frames 100 click of mouse = 30 sec.

File-> Save for WEB.