What is JavaScript?
- JavaScript is a programming language that adds interactivity and dynamic functionality to webpages
- It allows a webpage to manipulate HTML elements, perform calculations, handle user input, and more.
Purpose of JavaScript
- JavaScript is primarily used for client-side scripting, meaning it runs directly in the web browser of the user
- Its purpose is to enhance webpages by enabling interactive features, dynamic content, form validation, and data manipulation
- Interactive features include features like image sliders, drop-down menus, or interactive maps, like allowing users to zoom in and out on a Google Maps element embedded in the website
- Dynamic content could be loading more articles or posts when a user reaches the end of a page (infinite scrolling), or changing the content based on the user’s actions, such as showing different product descriptions when a user hovers over product images
- Form validation could be checking that all required fields have been filled in, that an email address has the correct format, or that passwords meet certain strength requirements
- Data manipulation could involve filtering a list of products based on user-selected criteria, sorting a table of data, or creating a dynamic chart that updates in real-time as new data comes in
- JavaScript can respond to user actions, update the content of HTML elements, and communicate with servers to retrieve or send data
Data Types in JavaScript
What is a data type in JavaScript?
- A data type is a classification of data into groups according to the kind of data they represent
- Computers use different data types to represent different types of data in a program
- The basic data types include:
- Integer: used to represent whole numbers, either positive or negative
- Examples: 10, -5, 0
- Real: used to represent numbers with a fractional part, either positive or negative
- Examples: 3.14, -2.5, 0.0
- Char: used to represent a single character such as a letter, digit or symbol
- Examples: ‘a’, ‘B’, ‘5’, ’$’
- String: used to represent a sequence of characters
- Examples: “Hello World”, “1234”, ”@#$%”
- Boolean: used to represent true or false values
- Examples: True, False
- Integer: used to represent whole numbers, either positive or negative
We can declare variables as follows:
| Syntax | let variable_name = value; |
|---|---|
| Example | let x = 5; |
It is important to choose the correct data type for a given situation to ensure accuracy and efficiency in the program.