JS Structure

Variable Declaration (var, let, const):

  • Command: var, let, const
  • Explanation: These commands are used to declare variables in JavaScript. var (Variable): Used for declaring variables globally or within a function, with function scope.
  • let (Block-Scoped Variable): Used for declaring variables within a block (e.g., a loop or an if statement) and has block scope.
  • const (Constant): Used for declaring variables with a constant value. It cannot be reassigned after declaration.

Example

var globalVariable = "I'm global";
let blockVariable = "I'm in a block";
const pi = 3.14159;

globalVariable = "I can be changed";
// blockVariable can only be accessed within its block.
// pi cannot be reassigned.

Conditional Statements (if, else, switch):

  • Command: if, else, switch
  • Explanation: These commands allow you to make decisions in your code based on conditions.
  • if: Checks a condition and executes a block of code if the condition is true.
  • else: Used in combination with if, it executes a block of code if the condition in if is false.
  • switch: Evaluates an expression against multiple possible case values and executes code based on the matching case.

Example

    let age = 18;

    if (age >= 18) {
        console.log("You can vote!");
    } else {
        console.log("You are too young to vote.");
    }

    let day = "Monday";

    switch (day) {
        case "Monday":
            console.log("It's the start of the week.");
            break;
        case "Friday":
            console.log("Weekend is coming!");
            break;
    default:
        console.log("It's a regular day.");
}

Function Declaration and Invocation:

  • Command: function
  • Explanation: Functions are reusable blocks of code that can be defined and called with specific inputs (arguments). They encapsulate a task and make your code more organized and maintainable.

Example

// Function declaration
function greet(name) {
    console.log("Hello, " + name + "!");
}

// Function invocation
greet("Sri"); // Output: Hello, Sri!
greet("Soham");   // Output: Hello, Soham!

Python Structure

Variable Assignment

  • Construct: variable_name = value
  • Explanation: In Python, you can create variables to store data. Variables are created when you assign a value to them. Python is dynamically typed, meaning you don’t need to declare the variable type explicitly.

Example

name = "Alice"
age = 30
pi = 3.14159

Conditional Statements (if, elif, else):

  • if condition: code to execute if the condition is True
  • elif another_condition: code to execute if the first condition is False and this condition is True

  • else: code to execute if none of the conditions are True

  • Explanation: Conditional statements allow you to make decisions in your code based on conditions.
  • if: Checks a condition and executes a block of code if the condition is True.
  • elif (short for “else if”): Used to check another condition if the previous if or elif condition is False.
  • else: Executes a block of code when none of the conditions in if or elif are True.

Example

age = 18

if age >= 18:
    print("You can vote!")
elif age >= 16:
    print("You can get a driver's license.")
else:
    print("You are too young for voting or driving.")

Function Definition and Invocation

Construct:

  • def function_name(parameters): #code inside the function return result

  • Explanation: Functions in Python are defined using the def keyword, followed by the function name and parameters. They allow you to encapsulate a block of code, make it reusable, and return values if needed.

Example

def greet(name):
    return "Hello, " + name + "!"

greeting = greet("Alice")
print(greeting)  # Output: Hello, Sri!

HTML Structure

HTML Elements

  • Construct: HTML elements are the building blocks of a web page. They are defined with tags, which are enclosed in angle brackets. Elements can be nested inside other elements, creating a hierarchical structure for web content.
  • Explanation: HTML elements define the structure and content of a web page. Some common elements include <h1> for headings, <p> for paragraphs, “” for links, and for images.

Example

<h1>This is a Heading</h1>
<p>This is a paragraph of text.</p>
<a href="https://www.example.com">Visit Example.com</a>
<img src="image.jpg" alt="An example image">

HTML Attributes

Example

<a href="https://www.example.com" target="_blank">Visit Example.com</a>
<img src="image.jpg" alt="An example image">

HTML Forms

  • Construct: HTML forms are used to collect user input. They are defined using the <form> element, and form controls such as text fields, radio buttons, checkboxes, and buttons are placed inside the form. The action attribute of the <form> element specifies where the form data is sent.
  • Explanation: Forms enable user interaction on web pages. When a user submits a form, the data is sent to the server for processing or used for client-side scripting.

Example

<form action="/submit" method="post">
    <label for="username">Username:</label>
    <input type="text" id="username" name="username" required>

    <label for="password">Password:</label>
    <input type="password" id="password" name="password" required>

    <input type="submit" value="Submit">
</form>