HTML5 Cheat Sheet 2026

The 30 highest-yield HTML5 facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. The element in HTML5 is used to: → Encode dates and times in a machine-readable format
2. Which canvas method is used to draw an arc or circle? → arc()
3. The element______ simply combines elements within an enclosing dd tag, though it may also correlate them with a caption defined by a dt tag. → object
4. Which HTML5 input type should be used to allow users to pick a color via a color picker? → color
5. What happens to a Dedicated Web Worker when the web page that created it is closed? → The worker is automatically terminated by the browser
6. What does the element typically contain? → Copyright, contact, and authorship information
7. Which canvas property sets the color or style used to fill shapes? → fillStyle
8. Which HTML5 element and attribute combination is essential for responsive web design on mobile devices? →
9. Which HTML5 element represents a scalar measurement within a known range, such as a disk usage indicator? →
10. What is the purpose of the HTML5 History API? → Allows manipulation of the browser session history without page reloads
11. What is the purpose of the 'placeholder' attribute in HTML5 form inputs? → Displays hint text inside the field that disappears when the user types
12. What HTML5 element is used to provide text tracks (subtitles or captions) for a video? →
13. Which HTML5 feature allows embedding scalable vector graphics directly in an HTML document? → Inline SVG
14. Which HTML5 attribute allows you to validate an input field value against a regular expression? → pattern
15. What is the purpose of the CSS 'clamp()' function in responsive design? → Sets a value that scales between a minimum and maximum based on a preferred value
16. What is the correct semantic element to use for the primary content area of a web page? →
17. Which HTML5 feature allows a web page to work offline by caching resources? → Service Workers with Cache API
18. Which HTML5 element is used to display a disclosure widget from which users can retrieve additional information? →
19. Which API is used to capture audio and video from a user's webcam and microphone? → MediaDevices.getUserMedia()
20. Which element is used inside or to specify multiple media file sources? →
21. Which postMessage() syntax correctly transfers (not copies) an ArrayBuffer to a Web Worker? → worker.postMessage(buffer, [buffer])
22. What is the role of the element in HTML5? → Specifies the base URL for all relative URLs in the document
23. What does the 'loop' attribute on an HTML5 element do? → Causes the audio to restart automatically when it finishes
24. What is the name of the canvas API? → immediate-mode
25. What does the 'message' event's 'data' property contain when received in a Web Worker? → The value passed to postMessage() by the sender, structured-cloned
26. Which of the following elements is used to highlight content in the same way as a highlighter pen is used to highlight key text in a book? → mark
27. The 'autocomplete' attribute on an HTML5 form field controls: → Whether the browser can automatically fill in the field value
28. Which HTML5 API gives JavaScript programmatic control over media playback, seeking, and volume? → HTMLMediaElement API
29. Which method of the Geolocation API watches for position changes and calls a callback continuously? → watchPosition()
30. What does the Geolocation API's getCurrentPosition() method do? → Retrieves the device's current geographic coordinates asynchronously