Harvard CS50W - Web Programming with Python & JavaScript Flashcards

Question 1

Django Models

Accepted Answer

Python classes that inherit from `models.Model` and define the database structure of a Django application. Each attribute corresponds to a database field.

Question 2

Django Views

Accepted Answer

Python functions or classes in `views.py` that accept a web `request` object and return an HTTP response, such as rendered HTML or JSON data.

Question 3

Django Templates & DTL Syntax

Accepted Answer

HTML files enhanced with Django Template Language (DTL). Use `{{ variable }}` for displaying variables and `{% tag %}` for logic like loops and conditionals.

Question 4

Django URL Routing

Accepted Answer

Maps URL patterns defined in `urls.py` via the `path()` function to specific view functions, using dynamic converters like `` or ``.

Question 5

Django Migrations (`makemigrations` vs `migrate`)

Accepted Answer

`python manage.py makemigrations` creates SQL migration instructions based on changes in `models.py`. `python manage.py migrate` applies those changes to the database.

Question 6

Django ORM Queries

Accepted Answer

Allows querying the database using Python code: `Model.objects.all()` gets all records, `.filter()` retrieves matching records, and `.get()` fetches a single unique record.

Question 7

Django Forms & ModelForms

Accepted Answer

Abstraction layer for handling HTML forms, validating user data, and (with `ModelForm`) automatically generating inputs and saving instances directly to the database model.

Question 8

JavaScript DOM Manipulation

Accepted Answer

Accessing and modifying HTML elements dynamically using methods like `document.querySelector('#id')`, updating text via `.textContent`, or altering structure via `.innerHTML`.

Question 9

JavaScript Event Listeners

Accepted Answer

Functions triggered by user interactions attached via `element.addEventListener(event, callback)`. Common events include `'click'`, `'submit'`, `'keydown'`, and `'DOMContentLoaded'`.

Question 10

AJAX & the JS `fetch()` API

Accepted Answer

Asynchronously requests data from a server without reloading the page using JavaScript Promises or `async/await` syntax: `fetch(url).then(res => res.json())`.

Question 11

HTML5 Semantic Elements

Accepted Answer

Structural tags that impart meaning to both developer and browser (e.g., `

`, `

Question 12

CSS Flexbox

Accepted Answer

A one-dimensional CSS layout module designed for distributing space along a single row or column using properties like `display: flex`, `justify-content`, and `align-items`.

Question 13

CSS Grid

Accepted Answer

A two-dimensional CSS layout system that manages both columns and rows simultaneously using properties like `grid-template-columns`, `grid-template-rows`, and `gap`.

Question 14

HTTP Request Methods

Accepted Answer

Standardized actions performed on web resources: `GET` (retrieve), `POST` (create), `PUT`/`PATCH` (update), and `DELETE` (remove).

Question 15

RESTful API Architecture

Accepted Answer

Representational State Transfer design standard using stateless requests, predictable URL endpoints (e.g., `/api/posts/`), and standard HTTP methods returning JSON payloads.

Question 16

Cross-Site Request Forgery (CSRF)

Accepted Answer

An attack forcing a logged-in user to execute unwanted actions on a trusted web application. Mitigated in Django using the `{% csrf_token %}` directive in POST forms.

Question 17

Cross-Site Scripting (XSS)

Accepted Answer

Vulnerability allowing attackers to inject malicious client-side code into web pages viewed by others. Django templates automatically auto-escape untrusted HTML input to prevent this.

Question 18

Single Page Application (SPA)

Accepted Answer

A web application that dynamically rewrites the current page using JavaScript and AJAX rather than loading entire new pages from the server.

Question 19

Server-Side Rendering (SSR) vs Client-Side Rendering (CSR)

Accepted Answer

SSR generates full HTML on the server for each request (Django's default). CSR sends minimal HTML and relies on browser JavaScript to build the DOM (React/Vue approach).

Question 20

HTTP Status Codes

Accepted Answer

3-digit server response status codes: `200 OK` (Success), `301` (Permanent Redirect), `400` (Bad Request), `403` (Forbidden), `404` (Not Found), and `500` (Internal Server Error).

Harvard CS50W - Web Programming with Python & JavaScript

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