Understanding JavaScript:

JavaScript, frequently shortened to JS, is a versatile programming language widely utilized in web development, web applications, and even game development. It allows developers to create responsive and interactive elements such as forms, animations, and user interface components. JavaScript is executed on the client side, meaning it runs in the user's web browser, enabling dynamic updates and changes to web pages without needing to reload the entire page. JavaScript is responsible for the majority of animations or actions triggered by user interactions such as clicking, hovering, or scrolling on a webpage. Interestingly, JS stands as one of the core technologies of the World Wide Web (WWW), alongside HTML and CSS.

What are the advantages of using JavaScript?

1) Enhanced User Experience: JavaScript enables developers to create dynamic and interactive features that enhance the overall user experience, such as animations, form validation, and real-time updates.

2) Compatibility with other programming languages: JavaScript's seamless integration with other programming languages makes it a top choice for developers in creating a wide range of applications. 

3) Client-Side Execution: JavaScript executes on the client side, meaning it runs in the user's web browser. This reduces server load and allows for faster rendering of web pages.

4) Cross-Browser Compatibility: JavaScript is supported by all modern web browsers, ensuring consistent performance across different platforms and devices.

5) Rich Ecosystem: JavaScript has an extensive list of libraries, frameworks, and plugins that extend its capabilities and simplify common tasks.

6) SEO-Friendly: JavaScript can be used to optimize web pages for search engines, improving visibility and ranking in search results.

7) Versatility: JavaScript can be used for a wide range of applications beyond web development, including server-side scripting, mobile app development, and game development.

Understanding jQuery

jQuery is a JavaScript library which focuses on making common JavaScript tasks simpler. The idealogy behind this library is to minimize time writing common JavaScript tasks. jQuery is cross-browser compatible - the output of the code will be as intended on any modern browser. Considering jQuery's versatility and simplicity, it is no wonder that jQuery has grown to become one of the most popular JavaScript libraries used by developers today.

What are the advantages of using jQuery?

1) Simplified Syntax: jQuery provides a simple and concise syntax for common JavaScript tasks, making it easier to write code and handle DOM manipulation, event handling, and animation.

2) Cross-Browser Compatibility: jQuery abstracts away browser-specific differences, ensuring consistent behaviour across different browsers and versions, thus saving developers time and effort in writing browser-specific code.

3) Extensive Library of Plugins: jQuery offers a vast ecosystem of plugins that extend its functionality and provide pre-built solutions for common tasks, such as form validation, image sliders, and AJAX requests, allowing developers to quickly add advanced features to their websites.

4) Faster Development: By providing a set of ready-to-use methods and utilities, jQuery speeds up the development process, enabling developers to build complex interactions and dynamic user interfaces with minimal effort.

5) Backward Compatibility: jQuery maintains backward compatibility with older versions, ensuring that websites and applications built with older jQuery versions continue to function properly without requiring major updates or modifications.

Finally, we answer the main question - Why do we use JavaScript and jQuery-based languages in website development?

Using JavaScript and jQuery-based languages in website development offers numerous advantages. JavaScript enables the creation of dynamic and interactive features, enhancing user experience and satisfaction. Its client-side execution reduces server load and ensures faster page rendering times, contributing to improved performance. Additionally, jQuery simplifies common JavaScript tasks with its concise syntax and extensive library of plugins, speeding up development and ensuring cross-browser compatibility. Together, these languages streamline development, enhance functionality, and ultimately result in more responsive, user-friendly websites.

Conclusion:

JavaScript and jQuery are essential tools in website development for creating dynamic and interactive features that enhance user experience. JavaScript, often called JS, operates on the user's web browser, allowing for real-time updates without reloading the entire page. It's responsible for animations and actions triggered by user interactions like clicking or scrolling. jQuery, a popular JavaScript library, simplifies common tasks, making coding easier and more efficient. It ensures consistency across different browsers and versions, speeding up development with its extensive library of plugins. Ultimately, using JavaScript and jQuery results in faster, more user-friendly websites that engage and satisfy visitors.