Online code editors are a fun and easy way to write codes in hypertext and style languages like HTML, CSS, JavaScript, JQuery and PHP etc. The online editors are also commonly referred to as Integrated Development Environments (IDE) and are available on internet for free. They also allow you to share the code with others using saved URL codes. is one of the most powerful and popular online code editors to write, run and debug your code. The editor also allows you to keep your work private or make it public in order to collaborate with other developers in your circle. Cloud9 makes developing much faster and testing extremely easy.  
Cloud9 is a modern and lightweight online code editor with supporting for over 90 languages. You can run cashes, databases and webservers straight from your web browser including Windows, OS X, Linux/Ubuntu and Chrome OS. Similarly, it supports almost all of coding languages such as Ruby, Python, Java, PHP, HTML 5 and CSS etc.
Visual studio online editor has been around for a while and it is a great source to edit your code in languages ranging from C#/VB and C++ to JavaScript and Python. It helps you code faster in addition to finding and fixing bugs without any hassle. Most importantly, Visual Studio guides you with live assistance and you can also use an auto-completion feature to increase your speed and accuracy.
Visual Studio

Coderun is a cross platform editor designed especially for the cloud. It allows you to use your browser to develop, deploy and debug various applications. You can use Coderun in combination with your desktop editor as well. Some of the languages Coderun supports are C#/.NET (3.5), PHP (5.1), JavaScript, HTML and CSS.