Web based IDEs allow programmers to write and compile code directly within a web browser without needing to install any software. They are developed using languages like PHP, HTML, and JavaScript. Some examples include codepad, Ideone, and CoolIDE. Web based IDEs provide features like syntax highlighting, file upload/download, screen splitting, and support for multiple simultaneous users. They offer advantages like being able to code from any internet-connected device and reducing lab maintenance costs compared to local IDE installations, but require an internet connection and cannot be accessed if the hosting server goes down.