What is DOM? Explain Directives in detail.

What is DOM?

The DOM (Document Object Model) is a programming interface for web documents. It represents the structure of a webpage as a tree of objects, where each element (like headings, paragraphs, images, links) becomes a node. Using DOM, programming languages like JavaScript can access, modify, add, or delete content and attributes dynamically.
👉 Example: Changing text or style of an element on a webpage using JavaScript.

What are Directives?

Directives are instructions in frameworks like Angular, Vue, or React (JSX attributes) that tell the browser or framework how to process or display elements in the DOM. They extend HTML’s behavior and make it more dynamic.

Types of Directives (in Angular as an example):

1. Component Directives

   • Define reusable components with their own logic, template, and style.

   • Example: <app-header></app-header> displays a custom header component.

2. Structural Directives

   • Change the DOM layout by adding or removing elements.

   • Examples:

     • *ngIf → Displays element if a condition is true.

     • *ngFor → Loops through a list and repeats elements.

3. Attribute Directives

   • Modify the appearance or behavior of elements.

   • Example: ngStyle, ngClass to apply styles or classes dynamically.

Summary

• DOM → Tree structure that represents web pages, allowing dynamic changes.

• Directives → Special instructions that control DOM behavior, layout, and styling in frameworks like Angular.