Greasemonkey and Tampermonkey enhance the capabilities of a web browser. These add-ons let you choose from thousands of user scripts that change the behavior and appearance of web pages. With Greasemonkey and Tampermonkey scripts, you can download Facebook and Instagram albums in one click, revamp Pandora's look and feel, and more.

Greasemonkey is only available for Firefox. To download it, visit the Greasemonkey download page on the Mozilla Add-ons website.

After Firefox restarts, a new button in the shape of a smiling monkey will appear in the browser's address bar. Select the monkey switch to toggle the Greasemonkey extension on and off. Select the down arrow next to the switch to change Greasemonkey settings and open the Firefox User Scripts management interface.

Tampermonkey is available for a number of web browsers. Like Greasemonkey, you control Tampermonkey with a switch in the address bar. This switch enables and disables functionality, checks for updates, creates your user script, and opens a dashboard where you manage Tampermonkey settings and installed scripts.