JavaScript Basics

Variables and Data Types

JavaScript allows you to store data using variables. Here are some common data types:

• Number: Represents numeric values (e.g., 10, 3.14).
• String: Represents text enclosed in single or double quotes (e.g., "Hello", 'World').
• Boolean: Represents truth values (true or false).
• Array: An ordered list of values.
• Object: A collection of key-value pairs.

        
          let name = "John";
          let age = 30;
          let isStudent = false;
          let numbers = [1, 2, 3, 4, 5];
          let person = {
            firstName: "Alice",
            lastName: "Smith"
          };

          console.log(name); // Output: John
          console.log(age);  // Output: 30
          console.log(isStudent); // Output: false
          console.log(numbers[0]); // Output: 1
          console.log(person.firstName); // Output: Alice
        
        

Operators

JavaScript provides various operators for performing operations:

• Arithmetic Operators: +, -, *, /, %
• Comparison Operators: ==, !=, >, <, >=, <=
• Logical Operators: &&, ||, !

        
          let x = 10;
          let y = 5;

          console.log(x + y); // Output: 15
          console.log(x > y); // Output: true
          console.log(x == 10 && y == 5); // Output: true
        
        

Conditional Statements (if...else)

You can use conditional statements to execute different code blocks based on specific conditions.

        
          let score = 85;

          if (score >= 90) {
            console.log("Excellent!");
          } else if (score >= 70) {
            console.log("Good");
          } else {
            console.log("Needs improvement");
          }