推荐十几款Firefox web开发插件（转载）

开发工具

1. Web Developer 1.1.8  
    https://addons.mozilla.org/en-US/firefox/addon/60
   by chrispederick 
   The Web Developer extension adds a menu and a toolbar with various web developer tools. 
   说明：超强的web分析工具，开发人员必装。

2. Firebug 1.5.0 
   https://addons.mozilla.org/en-US/firefox/addon/1843 
   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... 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. Visit the Firebug website for documentation, screen
   shots, and discussion forums: 
   说明：查看，编辑，Debug页面的CSS,HTML,JavaScript。超强的开发调试的工具，开发人员必装。

3. LinrLightWeb 0.2.1
   https://addons.mozilla.org/zh-CN/firefox/addon/14068 
   F*安装前，请确认您已安装Firebug插件，获取Firebug请访问:http://getfirebug.com/
   1. 开启网页编辑模式，随意编辑网页——Fiddler的好搭档；
   2. 超强Selector，查找操作标记；
   3. 刷新CSS，无需刷新整页；
   4. 快速设置CSS Sprites背景，鼠标拖移即可得到位置；
   5. 保持登录状态，Session不过期；禁用
   6. 同步发行IE版，Chrome版。
   说明：非常强的web开发工具。

4. View Source Char 2.7 
   https://addons.mozilla.org/en-US/firefox/addon/655
   by Jennifer Madden(MM) 
   Draws A Color-Coded Chart of a Web Page's Source Code. 
   说明：显示非常好看的源码, 分级缩进, 不同颜色区分。

5. Tamper Data 11.0.0 
   https://addons.mozilla.org/en-US/firefox/addon/966 
   Use tamperdata to view and modify HTTP/HTTPS headers and post parameters. 
   说明：查看 firefox 收发请求的 header, 特别是在发出请求前, 可以修改 header。

6. JavaScript Debuger 0.9.87.4 
   https://addons.mozilla.org/en-US/firefox/addon/216 
   Venkman
   is the code name for Mozilla's JavaScript Debugger. Venkman aims to
   provide a powerful JavaScript debugging environment for Mozilla based
   browsers. 
   说明：firefox 环境下的 JavaScript Debugger, 强大的脚本调试工具。

7. Live Http Headers 0.15 
   https://addons.mozilla.org/en-US/firefox/addon/3829 
   View HTTP headers of a page and while browsing. 
   说明：浏览页面同时记录所有 HTTP headers 。

8. Add N Edit Cookies 0.2.1.3 
   https://addons.mozilla.org/en-US/firefox/addon/573 
   Cookie Editor that allows you add and edit "session" and saved cookies. 
   说明：查看并且修改 cookies, 不方便的地方是显示所有浏览器的 cookies 而不仅是当前页。

9. XPath Checker 0.4.1 
   https://addons.mozilla.org/en-US/firefox/addon/1095 
   An
   interactive editor for XPath expressions. Choose 'View XPath' in the
   context menu and it will show the editor. You can edit the XPath
   expression and it incrementally updates the results. 
   说明：据说可以调试 XPath。

10. YSlow 2.0.6
    https://addons.mozilla.org/zh-cn/firefox/addon/5369
    YSlow analyzes web pages and why they're slow based on Yahoo!'s rules for high performance web sites. 
    说明：能够帮我们分析web页面比较慢的原因，它是基于Firebug的，也能分开浏览web页面的元素，比如js,css.

HTML验证

1. HTML Validator(based on CSE HTML Validator)1.2.3 
   https://addons.mozilla.org/en-US/firefox/addon/887 
   Validates
   HTML documents using the CSE HTML Validator engine for Windows.
   Requires CSE HTML Validator for Windows. The lite edition is available
   for free athttp://www.htmlvalidator.com/lite/
   说明：著名的 CSE HTML Validator 引擎。

2. Relaxed the HTML Validator 0.9.5 
   https://addons.mozilla.org/en-US/firefox/addon/3939 
   "Relaxed"
   is a HTML validator which validates HTML documents using it's own
   schema definitions written in Relax NG with embedded Schematron
   patterns.: 
   说明：直接在当前页面上进行 HTML validation, 界面清晰直观。

3. Total Validator 6.2.0  
    https://addons.mozilla.org/en-US/firefox/addon/2318 
   by Andy Halford 
   Perform
   multiple validations and take screen shots in one go. This 5-in-1
   validator works with external, internal, or local web pages using the
   Total Validator service or local copy of the desktop tool... 
   说明：把当前页面在 http://www.totalvalidator.com做HTML Validation,输出结果用红字进行了语法修正, 比较友好。不过由于通过其他网站验证, 速度有点慢, 并且结果不易保存。

页面设计

1. MeasureIt 0.3.92 
   https://addons.mozilla.org/en-US/firefox/addon/539 
   Draw out a ruler to get the pixel width and height of any elements on a webpage. 
   说明：可以测量页面上任何选择区域的长宽, 对界面设计人员非常有帮助。

2. ColorZilla 2.0.2 
   https://addons.mozilla.org/en-US/firefox/addon/271 
   Advanced Eyedropper, ColorPicker, Page Zoomer and other colorful goodies...
   说明：从页面, 或者调色板上取色, 同时可以缩放页面。

SEO广告

1. RankQuest SEO Toolbar 3.9.2 
   https://addons.mozilla.org/en-US/firefox/addon/1471 
   RankQuest
   SEO(Search Engine Optimization) Toolbar provides you quick access to
   more than 30 intuitive SEO tools. Alexa Rank and Page Rank provided by
   Alexa and Google respectively ensures the popularity of the site. Once
   you download and install the SEO Toolbar you are only one or two clicks
   away from carrying out most of your day to day SEO... 
   说明：SEO 工具插件, 访问一个页面时, 显示此页面的各种排名及 SEO 信息。

2. Adsense Preview 1.5 
   https://addons.mozilla.org/en-US/firefox/addon/2132 
   Preview the Google ads that may show on any web page. 
   说明：在当前页面上显示 Google ADs 帮助确定广告位置。

其他工具

1. HackBar 1.4.2 
   https://addons.mozilla.org/en-US/firefox/addon/3899 
   Simple security audit / Penetration test tool. 
   说明：快速对字符串进行各种编码的工具, MD5, Base64, URLencode, URLDecode。

2. Document Map 0.6.1 
   https://addons.mozilla.org/en-US/firefox/addon/475 
   Displays the current page's heading structure in the sidebar, allowing rapid navigation between... 
   说明：提供页面资源结构信息.。

3. IE View Lite 1.3.5 
   https://addons.mozilla.org/en-US/firefox/addon/1429

   This
   is a cut down version of IE View by Paul Roub, which is 47.4 KB. All
   the same UI and features are there. It has a right click menu item to
   open a page in IE and a list of sites to always open in IE. It can close
   tabs automatically and send... 
   说明：点右键可以选择在 IE 中打开页面, 有助于跨浏览器调试。

4. TimeStamp Converter 2.0.0 
   https://addons.mozilla.org/en-US/firefox/addon/2063 
   Converts dates and timestamps.Context menu option to convert the selected timestamp into a date. 
   说明：除去从上下文中转换, 还可以手动将 timestamp 时间戳与 date/time 转换。

5. TimestampDecode 0.1.8 
   https://addons.mozilla.org/en-US/firefox/addon/3208 
   Treats the selected number as a timestamp and displays a decoded date/time. 
   说明：将选中的数字作为 timestamp 时间戳转换为 date/time。

6. Fire Encrypter 4.0 
   https://addons.mozilla.org/en-US/firefox/addon/2063 
   FireEncrypter
   is an Firefox extension which gives you encryption/decryption and
   hashing functionalities right from your Firefox browser, mostly useful
   for developers or for education & fun... 
   说明：将文字加密成各种算法的密文, 甚至包括摩尔斯码。

7. Add-in-one Sidebar   
   https://addons.mozilla.org/en-US/firefox/addon/1027 
   AiOS
   lets you open various windows as sidebar panels, and quickly switch
   between them. So it put an end to the window chaos! In addition to
   bookmarks and history it opens dialogues such as downloads, add-ons and
   more in the sidebar. 
   说明：在浏览器左侧增加打开书签, 历史, 插件等的工具条。