User Agent and JS Manager is a powerful Chrome extension designed for developers and testers who need to analyze website functionality across different environments. This tool allows users to switch user agents effortlessly, enabling them to see how websites appear to various crawlers and browsers. In addition, it provides the capability to toggle JavaScript execution, which is essential for debugging features that depend on JavaScript, such as form submissions and server-side rendering. Users can also manage cookie settings on a per-site basis, ensuring a comprehensive testing environment.

This extension is particularly useful for verifying how search crawlers and social media platforms render web pages, testing form submissions without JavaScript, and managing privacy settings for different domains. It automatically applies user configurations when revisiting sites, making it convenient and efficient. Notably, all data remains local to the user's device, ensuring privacy and security while using the extension.