Web Application Model Web Development

 

Core Components of Web Applications

Certainly, you've highlighted the core components of web applications in a concise format. Here's a brief overview of each of these components: 1. UI (User Interface) - Front End:

• - DOM (Document Object Model):** The DOM represents the structure of a web page and allows dynamic manipulation of page content using JavaScript.

- Framework:** Front-end frameworks like React, Angular, or Vue.js provide tools and structures for building user interfaces. 2. Request Layer - Web API: - Web API (Application Programming Interface):** This layer handles incoming requests from clients and manages the communication between the client and the back end. It often follows the principles of REST (Representational State Transfer) or GraphQL. 3. Back End:

• - Database: This is where data is stored and retrieved. Various types of databases can be used, such as SQL databases (e.g., MySQL) or NoSQL databases (e.g., MongoDB).
• - Logic: The back end is responsible for the business logic of the web application. It processes data, enforces rules, and handles various operations.

 front-end web development. Here's a bit more detail on this:

• 1. HTML (Hypertext Markup Language): HTML is the standard markup language for creating the structure and content of web pages. It's essential for defining the elements and layout of a webpage.
• 2. CSS (Cascading Style Sheets): CSS is used for styling and presentation. It allows you to control the visual appearance of HTML elements, including layout, colors, fonts, and more.
• 3. JavaScript: JavaScript is a versatile and powerful scripting language that adds interactivity and dynamic behavior to web pages. It's commonly used for creating responsive user interfaces, handling user interactions, and making web applications more engaging.

While HTML, CSS, and JavaScript are the primary languages for front-end development, Java applets, which you mentioned, were used in the past for creating interactive web content. However, applets have become less popular due to security concerns, browser compatibility issues, and the rise of more modern web technologies. JavaScript has emerged as the de facto standard for web interactivity.

In addition to JavaScript, there are many JavaScript frameworks and libraries available, such as React, Angular, and Vue.js, which simplify and enhance the development of complex front-end applications. These frameworks offer various features and tools to make web development more efficient.

DOM (Document Object Model)

Here's a bit more detail on the points you mentioned:

1. Manipulation of DOM Objects: With the DOM, developers can use JavaScript to access and manipulate DOM objects, enabling them to change the content, appearance (color, transparency, position), behavior, and even add or remove elements on a web page. This dynamic manipulation is fundamental to creating interactive and responsive web applications.

2. Every HTML Tag as a DOM Object: As you mentioned, every HTML tag within a web page becomes a DOM object when the page is loaded in a browser. This means that you can interact with and modify these elements using JavaScript, allowing for real-time updates and user interactions.

DOM

What is a Framework?

1. Purpose of a Framework:

•    - A software framework is primarily designed to reduce the overhead in web development. It provides a structured foundation that developers can build upon, allowing them to focus on application-specific features rather than reinventing common functionalities.

2. Types of Framework Architectures:

•    - Model-View-Controller (MVC):** MVC is a common architectural pattern used in web frameworks. It separates the application into three interconnected components: the Model (data and business logic), the View (user interface), and the Controller (handles user input and controls the flow of the application).
•    - Push vs. Pull-Based:** These terms refer to how data is transmitted in the framework. Push-based frameworks involve data being pushed to the client when it changes. Pull-based frameworks require the client to request data when needed.

3. Examples of Frameworks with Architectures:

•    - Push-Based (MVC) Frameworks: Examples include Django, Ruby on Rails, Symphony , and Stripes. These frameworks follow a push-based architecture, where data is pushed to the client when it changes.
•    - Pull-Based (Component-Based) Frameworks: Examples include Lift, Angular 2, and React. They are based on a pull-based architecture, where the client requests data as needed. These frameworks are often organized into a component-based structure.

4. Three-Tier Organization:

   - Many web applications are organized into a three-tier architecture:

•      - Client: Typically, the user's web browser running HTML, JavaScript, and CSS.
•      - Application: This tier contains the business logic of the application, often managed by a server, and can be a part of server-side frameworks.
•      - Database: Where data storage and retrieval occur.

5. Types of Frameworks:

•    - Server-Side Frameworks: These frameworks are used for building the server-side of web applications. Examples include Django and Ruby on Rails.
•    - Client-Side Frameworks: These are designed to enhance the user experience in the browser, offering features for dynamic web applications. Examples include Angular, React, and Vie.

You've listed some popular JavaScript frameworks and libraries commonly used in web development. Here's a brief overview of each:

1. Angular (formerly AngularJS and Angular 2+):

   - Angular is a comprehensive front-end framework developed by Google. It's used for building dynamic, single-page web applications. Angular 2 and later versions introduced significant changes and improvements over the original AngularJS.

2. ASP.NET:

   - ASP.NET is a server-side framework developed by Microsoft for building web applications. It includes a range of tools and technologies, such as ASP.NET Web Forms, ASP.NET MVC, and ASP.NET Core, for creating web applications using C#.

3. React:

   - React is a widely popular JavaScript library created by Facebook. It's used for building user interfaces, focusing on component-based development and efficient UI updates. React is often used in combination with other technologies, like Redux for state management.

4. Polymer 1.0:

   - Polymer is a JavaScript library developed by Google for creating web components. It helps developers build reusable and encapsulated web elements. Note that Polymer has evolved, and later versions have been released since Polymer 1.0.

5. Ember.js:

   - Ember.js is a front-end framework for building ambitious web applications. It provides a structured and opinionated way to develop web apps with conventions and best practices built-in.

6. Vue.js:

   - Vue.js is a progressive JavaScript framework for building user interfaces. It's known for its simplicity and flexibility, making it easy for developers to integrate into projects of various sizes.