5-21-12

by tiffany may

38 Add-ons in this Collection

Video DownloadHelper by mig

Rated 4 out of 5 stars 7,584 reviews

4,391,164 users

The easy way to download and convert Web videos from hundreds of YouTube-like sites.

Firebug by Joe Hewitt, Jan Odvarko, others

Rated 4 out of 5 stars 1,932 reviews

1,777,892 users

Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page...

Greasemonkey by Anthony Lieuallen, Aaron Boodman, others

Rated 4 out of 5 stars 1,018 reviews

1,144,697 users

Customize the way a web page displays or behaves, by using small bits of JavaScript.

User Agent Switcher by chrispederick

Rated 4 out of 5 stars 267 reviews

295,356 users

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Full Web Page Screenshots (♥♥♥♥♥) by susbox

FireShot makes full web page screenshots. Demo: http://bit.ly/RlBQMV

Screenshots can be quickly captured and:

― Saved as Image or PDF
― Sent to clipboard
― Printed
― Annotated *
― Uploaded *
― E-Mailed *

* OS Windows only

Web Developer by chrispederick

Rated 5 out of 5 stars 254 reviews

405,643 users

The Web Developer extension adds various web developer tools to the browser.

Tamper Data by Adam Judson

Rated 4 out of 5 stars 143 reviews

91,937 users

Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...

Xmarks Sync by Xmarks Inc.

Rated 4 out of 5 stars 2,591 reviews

281,341 users

Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!

ColorZilla by Alex Sirota

Rated 5 out of 5 stars 316 reviews

224,809 users

Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...

JavaScript Debugger by James Ross, Robert Ginda, others

Rated 4 out of 5 stars 49 reviews

99,863 users

As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.

Venkman is the code name for Mozilla's JavaScript Debugger. Venkman aimed to provide a powerful JavaScript debugging environment for Mozilla based browsers.

MeasureIt by Kevin Freitas

Rated 4 out of 5 stars 360 reviews

116,494 users

Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.

HttpFox by Martin Theimer

Rated 4 out of 5 stars 172 reviews

72,450 users

An HTTP analyzer addon for Firefox

YSlow by YSlow

Rated 3 out of 5 stars 219 reviews

62,776 users

YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages.
http://yslow.org is the official open source website.

Html Validator by Marc Gueury

Rated 4 out of 5 stars 215 reviews

45,295 users

HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon

For Online HTML 5 validation, you need 0.962
http://users.skynet.be/mgueury/mozilla

View Cookies by Edwin Martin

Rated 4 out of 5 stars 46 reviews

24,219 users

It adds a tab to the Page Info dialog box, which shows the cookies belonging to the current page.
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