Blockly is a client-side JavaScript library for creating visual block programming languages and editors. It is a project of Google and is open-source under the Apache 2.0 License. It typically runs in a web browser, and visually resembles Scratch. Blockly uses visual blocks that link together to make writing code easier, and can generate JavaScript, Python, PHP or Dart code. It can also be customized to generate code in any textual computer language.[1]
List of Free online Blockly IDE: