JavaScript Fundamentals: A Beginner's Guide to the Basics || Learn JS

JavaScript is a widely used programming language that is primarily used for creating interactive web pages and web applications. Here are some basic concepts in JavaScript:

1. Variables: Variables are used to store data values. In JavaScript, you can declare variables using the var, let, or const keywords. For example:

     

        var name = "John";

        let age = 25;

        const PI = 3.14;

2. Data types: JavaScript has several built-in data types, including numbers, strings, booleans, arrays, objects, and more. You don't need to explicitly declare the data type of a variable; JavaScript automatically assigns it based on the value assigned. For example:

     

         var number = 10;

        var name = "John";

        var isTrue = true;

        var colors = ["red", "blue", "green"];

        var person = { name: "John", age: 25 };

       

3. Operators: JavaScript supports various operators for performing arithmetic, assignment, comparison, logical operations, and more. For example:

 

         var sum = 5 + 3;

        var isGreater = (10 > 5);

        var result = (true && false);

4. Conditional statements: Conditional statements allow you to execute different blocks of code based on specified conditions. JavaScript includes if, else if, and else statements. For example:

    

         var num = 10;

        if (num > 0) {

          console.log("Positive number");

        } else if (num < 0) {

          console.log("Negative number");

        } else {

          console.log("Zero");

        }

       

5. Loops: Loops are used to repeatedly execute a block of code. JavaScript provides for, while, and do-while loops. For example:

 

            for (var i = 0; i < 5; i++) {

            console.log(i);

          }

         

          var j = 0;

          while (j < 5) {

            console.log(j);

            j++;

          }

6. Functions: Functions are reusable blocks of code that perform a specific task. You can define your own functions in JavaScript. For example:

 

           function greet(name) {

            console.log("Hello, " + name + "!");

          }

         

          greet("John");