1. 1. Syntax: Ext JS is a JavaScript framework that follows a declarative syntax, allowing developers to define user interface components using an Ext JS-specific markup language called Ext JS Component Query Language. On the other hand, axios is a promise-based HTTP client for JavaScript that follows an imperative syntax, where developers make HTTP requests using functions and passing in parameters.
2. 2. Purpose: Ext JS is primarily designed for building complex web applications with highly customizable UI components. It provides a rich set of built-in components, such as grids, forms, and charts, and offers extensive support for data manipulation and binding. In contrast, axios is focused solely on making HTTP requests and handling responses in a simpler and more lightweight manner, making it suitable for a wide range of use cases beyond web application development.
3. 3. Dependency: Ext JS has a larger footprint and requires the use of its own library, which includes its UI components and framework features. It is tightly integrated with its own ecosystem and may have dependencies on specific versions of other libraries. On the other hand, axios is a standalone library that does not have any external dependencies and can be used with any JavaScript framework or library, providing more flexibility in terms of integrating it into existing projects.
4. 4. Browser and Server Support: Ext JS is designed to work well across different browsers and supports older versions as well, providing consistent behavior and user experience. It also offers support for back-end integration with various server-side technologies. In comparison, axios is compatible with all modern browsers and can be used both in front-end JavaScript and back-end Node.js environments, making it versatile in terms of server support.
5. 5. Error Handling: Ext JS provides comprehensive error handling mechanisms, including built-in validators, form validation support, and customizable error messages. It also offers robust error handling for server-side errors. On the other hand, axios has a more straightforward error handling process, where developers can access error responses through promise rejection, and can implement custom error handling based on the HTTP status codes returned.
6. 6. Community and Documentation: Ext JS has an active and vibrant community, providing extensive resources, forums, and support for developers. It offers comprehensive documentation and regular updates, ensuring developers have access to the latest features and improvements. On the other hand, axios has gained popularity due to its simplicity and ease of use, with a growing community and readily available documentation and examples.

In Summary, Ext JS and axios have key differences in terms of syntax, purpose, dependencies, browser and server support, error handling, and community/documentation. Ext JS is a comprehensive JavaScript framework for building complex web applications, while axios is a lightweight HTTP client primarily focused on making requests.