1. Firebug Lite ButtonFirebug Lite Button

Open firebug lite on opened web page. Simply install this extension, click on extension button and firebug lite will be started.

Firebug lite button allows you quickly and easy open Firebug lite in your opened web page. This button is only shortcut to Firebug Lite that will open Firebug Lite from the Internet.

opera logo web extensions

2.  OMeasure!

Simple measuring tool for web developers. WARNING! Please reload page you want to measure just after extension installation. Otherwise it won’t work. With OMeasure! you can measure any element or section on website you develop. There would be size of selected area in pixels.

How to use it: 1. Click on OMeasure! button so that there there would be “on” on the button.
2. Drag desired area you want to measure.
3. You can resize selected area by dragging a corner.

3. Edit the Page

Edit the page like a WYSIWYG editor. Toggles the ‘Design Mode’ so that you can edit the contents of the page.

4. HTML5 Outliner

Outlines a web page’s HTML5 elements Displays an outline of the current page using the HTML5 outlining algorithm. This extension is a port of the bookmarklet at http://code.google.com/p/h5o/

5. Easy User CSS

Add CSS to any website – I think the name tells a lot about extension’s functionality. Before this extension you had to create new file for every site where you wanted to have User CSS. Thanks to my extension you can just click on a button, write the css rules and press “save” – that’s all! You can also use “Live preview” that shows the effect of styling immediately during writing the CSS rules.

– Grey background of textarea means, that it’s not possible to edit the User CSS (sites loaded before you installed this extension, speeddial, etc…). If the background is grey on regular site, try to reload the site.
– Extensions might not work on sites with dynamically created iframes
– Even with “Live preview” turned on, you have to use “save” button for permanent changes!!

6. Validator

Easily Validates pages with W3C’s Validator. Validator enables users to easily Validate pages with the W3C’s HTML Validator. How to use the extension is simple, just click on the button and the page will be examined. This extension was made in mind for developers and web enthusiasts. Note: This only validates online pages.

7. Block Yourself from Analytics

Block your Google Analytics activity for the websites you own, no more false stats. This extension is for web developers to block their own visits for their websites thus avoiding false stats. It is not meant to block Google Analytics scripts for all websites. Extension uses two different methods to block GA, better method requires User JS Storage so I recommend you turn on User JS Storage by entering something higher then zero in opera:config#PersistentStorage|UserJSStorageQuota.

8. Images dimensions

Check quickly width and height of selected image

Get dimensions from selected images. Width and height will be shown in frame placed on right site of page (you can change placement of that frame). You can hide information frame by clicking on it. Additional informations about image will be shown too if these informations will be available from image.

9. URL Encoder/Decoder

A simple URL encoder/decoder. Just copy and paste the string you want to encode/decode in the extension textarea and click the encode/decode button, or enable the current tab URL auto-decode.

10. JsonViewer

Formats and highlights JSON data loaded from file or server String and boolean values are highlighted with blue, numbers – with green, null values – with red color. I plan to add folding of arrays and objects in newer versions of this extension.

You can use http://ratesby.appspot.com/values page to test this extension

Note: if server returns content type “application/json” for JSON data then Opera will prompt to download JSON file because Opera doesn’t know such content type.
To make it displayed by Opera instead of downloading it:
1. Go to Opera preferences -> Advanced -> Downloads.
2. Press Add button (if you haven’t added content type “application/json” previously. Otherwise just edit it and go to item 4).
3. Enter MIME type “application/json” (without quotes) and file extension “json” (also without quotes).
4. Select action “Open with Opera”.
5. Press Ok buttons to apply your changes.

11. NoFollow

Outlines nofollow links on webpages. Outlines links with rel=”nofollow” and links on pages with nofollow robots meta tag.
– set your own CSS styles for outlining nofollow links (separate css for nofollow meta tag and nofollow link)
– ability to disable or enable extension for certain websites

12. Outbound Links

Displays the number of outbound links in the current webpage, in addition to other link statistics when the button is clicked.

This extension displays the number of outbound links in the webpages you view in the extensions toolbar badge. When you click the badge a small report pops up with other information including the total number of links, unique links, outbound links, unique outbound links, outbound hosts, and outbound nofollow links.

NOTE: In order for this extension to work on pages without a <script> tag, the options “Always Load User JavaScript” and “User Javascript” need to be enabled via opera:config. These two options are not enabled by default.

13. Auto-Ipsum

Transforms special HTML comments found in webpages you’re developing into blocks of Lorem Ipsum text.

When this extension is enabled, every webpage you view will be checked for special HTML comments that specify numbers or ranges of words, sentences, or paragraphs. For instance, “<!– 2-5 sentences –>” or “<!– 3 words –>”.

14. Xdebug launcher

Starts a Xdebug session from Opera. An extension for PHP developers, which adds ability to start a Xdebug session from Opera.

15. PageRank Checker

Alexa and Google PageRank extension for Opera.

Display PageRank for active website. It can display Alexa Linking in, Alexa Review and Alexa Ranking when extension button clicked.

2 thoughts on “15 Best Web Development Extensions For Opera”

  1. Thank you for sharing the information with us. As the internet marketing is so important for all the business, we should develop more strategies for the web development. Besides the web design, we should increase traffic to the web site to bring us more business in the future.

  2. Instead of developing eye catcher for opera browser someone should develop secure opera coded in assembler optimized to the roof and 1 milion percent isolated from the os for god ! Browsers are getting from bad to worse ! Frequently crashing/loppholes for hacking sript and java script arent trustworthy and so on !!! 1 security 2. stability 3. ant hen all other things !!!! Opera is getting like Microsoft !!!! Never enough power to run it and on mobile one have beter security as on pc !!! How cool/not cool ist that ??? If microsoft wont secure windows at least web browser should do that due to browser is the window in to the insecure not trust worthy internet !!!!

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