Web apps are taking the places of desktop apps and the same is happening to our development tools as well.

ICEcoder is an open source and web-based IDE that is built with PHP and works fast.

It works by simply dropping its app folder to anywhere we prefer and any files there (and inside subfolders) are ready to be edited.

The syntax of the code is highlighted, broken tags and HTML structure are displayed + allows selecting them easily.

There is support for Emmet and comes bundled with Adminer (for managing MySQL).

ICEcoder has a powerful JavaScript API for easily interacting with it and it works with many popular languages (PHP, JS, CSS, LESS, Ruby, etc.).

When working on a project, after each CSS or JavaScript update, the need to refresh the browser is a time-loss (and it is usually done 10s of times).

Tincr, a Chrome extension, solves this by integrating itself into Chrome’s Developer Tools and auto-refreshing the browser once these files are changed.

It is not bound to any IDE and works with all of them. There are several built-in project types (Ruby on Rails, Chrome extensions, Atlasian projects..) and custom ones can be created for any custom CSS/JS structure.

Also, it -kinda- converts the Developer Tools into an IDE by adding an auto-save feature to changes made to the code from Developer Tools

You may have heard of Zen Coding before and it now has a new name and website: Emmet.io.

Emmet is an editor plugin which has versions for many popular editors like Notepad++, Aptana, Coda, TextMate, Komodo Edit and more.

Once installed, using a CSS-like syntax, it is possible to create bulk HTML and CSS code (or nay other programming language code) with a single line for coding quickly.

For example, it can transform this command: ul#nav>li.item$*4>a{Item $} into an HTML unordered list with 4 items.

It can also generate Lorem Ipsum text and much more complex outputs than the example above.

There are various actions integrated for fastening the stuff more like splitting-joining, merging lines, browsing through important code points, etc.

Working completely online is not only a getting popular trend but also something that happens slowly in the background almost without us realizing it.

Many of us have online storage accounts to host our documents/codes, lots of web apps exist to help us accomplish our daily tasks (image editors, cross-browser testing tools, etc.).

Orion, by Eclipse, is an open source and online IDE application (that is alternative to others) which can be a good alternative for anyone willing to create code online.

It has 2 versions, hosted or self-hosted, and the self-hosted version requires Java to run.

The application supports working with multiple projects, creating files/folders, FTP and there is Firebug + Git integration.

Orion is extensible with its plugin system and it is well-documented.

Codiad is an open source web-based IDE application for writing and editing code online.

The application is built with PHP and doesn't require a SQL database but stores the data in JSON formatted PHP files.

Its interface has 3 panels:

• project/file manager
• code editor
• menu/actions 

where the left and right panels can be hidden on request for maximum coding space.

Codiad is capable of handling multiple projects with a single installation and any number of users can login to the application.

It removes the need of creating a local test/development environment and enables anyone to keep all data + the development process in a remote server.

Even though the application is still in an early development phase, it is mentioned to be stable and has an API for further improvements.

When writing CSS code, adding CSS properties in a specific order for each rule helps reading it easier so much.

For anyone who already does that or not, CSScomb, a free service sorts CSS properties in any order you want (and, their default order is pretty good too -from the most to least important-).

It works with both single + multi-line CSS code and besides the online version, there are add-ons provided for the most popular IDEs.

If you are always developing with a specific language, using a development tool that is built specifically for that language can ease the process.

NINJA-IDE is an open source and free development tool that focuses on Python developers at first but has support for code highlighting for various languages.

It has a handy code locator which enables us to access to any file, function or class inside the projects and a debugger that can highlight static and PEP8 errors in the document.

The application allows managing Python Project automatically, saving descriptive information about them and letting the user to perform file management related task in the IDE itself.

NINJA-IDE is highly extensible with its plugin support and there are already multiple plugins like a snippet manager or Git integration.

P.S. It works in all major operating systems.

Brackets is an open source code editor (IDE), built by Adobe, which is created with only client-side web technologies like HTML-CSS and JavaScript.

The editor focuses on simplicity and, rather than too many panels, the quick-edit UI is the main thing.

A "live development" feature syncs a browser with the editor and displays any changes instantly.

It is integrated with the Chrome's Developer Tools and JSLint for debugging.

Brackets, although being web-based, works in a native shell (Win & Mac versions available) to reach the filesystem.

Mobello is an open source JavaScript UI framework that simplifies developing mobile web apps.

The framework aims to provide a native-like experience in mobile, it is optimized for touch events and has 20+ widely-used UI components.

It also has an IDE, named Mobello Studio, that focuses on building mobile apps with HTML5, CS3 and the Mobello framework..

Mobello Studio has a drag 'n' drop enabled  visual design editor, a JavaScript debugger and built-in mobile device emulator.

The API of the framework is documented in detail and it can be a good alternative to other popular ones if improved regularly.

If you like working with lightweight editors when coding or willing to switch to a lighter one, Intype is a very nice option.

It is a fast-loading text editor that has support for syntax highlighting and snippets on most of the popular languages (and new ones are being added regularly).

The application can handle multiple projects, allows browsing/managing the files of them and comes with advanced editing features like:

• the ability to select multiple text and editing at once
• smart column selection (selecting all text inside an unordered list)
• snippet insertion
• and more..

P.S. It also has a "distraction-free" editing mode which is great for focusing on the code and nothing else.