- 01Setting Up (What You'll Need)
- 02Your First HTML
- 03Lists and Links
- 04Adding Color with CSS
- 05CSS Selectors and Classes
- 06Layout with Flexbox
- 07Trying Out Images and Tables
- 08Trying Out Form Controls
- 09Understanding the Box Model
- 10Intro to Responsive Design (Media Queries)
- 11CSS Variables (Custom Properties)
- 12Layout with CSS Grid
- 13Adding an Animation
- 14How to Write Comments
- 15Adding Interaction with Pseudo-Classes (:hover)
- 16CSS's :not() and Multi-Condition Selectors
- 17The Basics of Meta Tags and SEO
- 18The Basics of Accessibility (alt and aria-label)
- 19Trying Out data Attributes (data-*)
- 20CSS Transitions (Smooth Hover Changes)
- 21iframe (Embedding Another Page)
- 22position (Precisely Positioning an Element)
- 23z-index (Specifying Stacking Order)
- 24The Basics of localStorage (Saving Data in the Browser)
- 25The video and audio Tags (Embedding Media)
- 26Advanced Tables (colspan and rowspan)
- 27The Basics of CSS Specificity
- 28The Basics of SVG (Drawing Vector Images)
- 29Advanced Flexbox (Wrapping and Growing)
- 30Form Validation (required and pattern)
- 31Advanced CSS Grid (grid-template-areas)
- 32The details and summary Tags (Building a Collapsible Panel)
- 33CSS Counters (Automatic Numbering)
- 34Fluid Font Sizes with clamp()
- 35prefers-color-scheme (Dark Mode Support)
- 36Building a Slider with input type=range
- 37Fixing an Aspect Ratio with aspect-ratio
- 38Adjusting How an Image Displays with object-fit
- 39Rotating and Scaling with transform
- 40Serving Responsive Images with the picture Tag
- 41Showing Keyboard Focus with :focus-visible
- 42Scrolling Smoothly with scroll-behavior
- 43Switching Layouts Per-Component with Container Queries
- 44Creating a Frosted-Glass Effect with backdrop-filter
- 45Building a Flexible Grid with repeat() and minmax()
- 46Fixing a Header in Place with position: sticky
- 47Adding Pseudo-Elements with ::before and ::after
- 48Truncating Long Text with an Ellipsis Using text-overflow
- 49Using a Calculated Value in CSS with calc()
- 50[Applied] Build a Simple Website
How to Write Comments
In this lesson you'll learn how to write comments in HTML and CSS so you can write code that's easy to understand even when you come back to it later. This is for people searching "HTML how to comment out."
A comment is a "note for humans" that has no effect on how the page displays. In HTML, wrapping something in <!-- --> makes it a comment; in CSS, it's /* */. This is useful as an explanation for yourself when you look back later, or for anyone working alongside you.
The sample code uses an HTML comment to mark a section boundary, and a CSS comment to note the intent behind a style. You can also confirm, from the fact that the commented-out <p> tag isn't actually displayed, that a comment is a mechanism for skipping processing.
A common beginner stumbling block is that HTML and CSS use different comment syntax. Using HTML's <!-- --> inside CSS, or CSS's /* */ inside HTML, won't be correctly recognized as a comment. You need to remember the right syntax for each language.
Leaving notes like "what is this section for" or "why does this style use this value" lets you grasp the code without confusion even as it grows long. This is also used to temporarily disable code (commenting it out), a way of writing that's essential in real work too.
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