Questions
HTML questions
Choose a question page, learn the concept, then test your understanding with a quiz.
How to Store JavaScript Objects in localStorage and sessionStorage
Learn why localStorage stores strings only and how to safely save and retrieve JavaScript objects using JSON.stringify and JSON.parse.
How to Style a Checkbox Using CSS
Learn why checkbox styling is limited by default and how to customize checkboxes with CSS using practical beginner-friendly examples.
How to Style a Select Dropdown with CSS Only
Learn what CSS can and cannot do when styling HTML select dropdowns, including browser limits, practical techniques, and fallbacks.
How to Style an iframe with CSS in HTML
Learn how CSS works with iframes, why parent page styles do not automatically apply, and practical ways to style iframe content safely.
How to Style an input type="file" Button in HTML and CSS
Learn how to style an HTML file input button using CSS, labels, and accessible patterns with practical examples.
How to Validate an Email Address in JavaScript
Learn how to validate an email address in JavaScript using simple checks, regex, and browser tools with beginner-friendly examples.
How to Vertically Align Elements in a div with CSS
Learn how to vertically align images and headings inside a div using modern CSS, including flexbox and absolute positioning.
How to Vertically Align Text in a div with CSS
Learn how vertical alignment works in CSS, why `vertical-align` does not center normal div text, and the best ways to center content.
How to Vertically Center Text with CSS
Learn how to vertically center text with CSS using flexbox, line-height, and other practical techniques for modern layouts.
How to Vertically Center a div in CSS Across Browsers
Learn practical CSS techniques to vertically center a div, including older browser limitations and reliable modern solutions.
How to Wrap Text in a pre Tag in HTML
Learn how to make text wrap inside an HTML pre tag using CSS while preserving whitespace and formatting for code and debug output.
Include One HTML File in Another HTML File
Learn how to reuse HTML content in another page using iframes, server-side includes, templates, and JavaScript fetch patterns.
JavaScript DOM Ready: Vanilla JS Equivalent of jQuery $(document).ready()
Learn the vanilla JavaScript equivalent of jQuery $(document).ready() using DOMContentLoaded, load, and safe cross-browser patterns.
JavaScript Links: Should You Use href="#" or javascript:void(0)?
Learn why href="#" and javascript:void(0) are usually poor choices, and what to use instead for JavaScript actions.
Local Storage vs Cookies in JavaScript: Key Differences and When to Use Each
Learn the real differences between cookies and localStorage in JavaScript, including performance, security, size, and best use cases.
Markdown Links That Open in a New Tab: target="_blank" Explained
Learn whether Markdown supports target="_blank", how to use HTML safely, and how to design portable Markdown link extensions.
Matching Opening HTML Tags with Regex in JavaScript
Learn how to match opening HTML tags while excluding self-closing tags, and understand the limits of regex for HTML parsing.
Overlay One Div Over Another Div with CSS Positioning
Learn how to overlay sibling divs with CSS positioning, center an icon vertically, and align it to the right edge of a navigation bar.
Position a Div at the Bottom of Its Container with CSS Flexbox
Learn how to place a div at the bottom of its container without absolute positioning using Flexbox, auto margins, and layout rules.
Prevent iPhone Safari Input Auto-Zoom with CSS
Learn why iPhone Safari zooms text inputs and how to prevent focus zoom safely using a 16px CSS font size and responsive viewport settings.