Understanding HTML comments and their importance in code.
Jul 02, 2025 pm 03:32 PMHTML comments are not displayed in the browser, but can improve code readability and maintenance. 1. Improve readability: help developers quickly understand the code structure; 2. Convenient debugging: temporarily hide the code test effect; 3. Marking area: clearly identify the purpose of the code block; 4. Team collaboration: facilitate others to understand development ideas. When using it, avoid nesting, over-commenting, maintaining updates, unifying styles and avoiding leakage of sensitive information.
HTML comments don't appear in the browser, but they are very useful to developers. Simply put, comments are tools used to explain, mark or temporarily hide some of the content of the code.

Why use comments in HTML?
The main function of comments is to improve code readability and maintenance. Especially when multiple people collaborate or project time span is long, clear annotations can help you and others quickly understand the code structure.

- Convenient debugging : You can temporarily comment out a certain piece of code to test the page effect.
- Marking area : For example, use comments to indicate the function of a certain block, such as
<!-- 導(dǎo)航欄開始-->
and<!-- 導(dǎo)航欄結(jié)束-->
. - Teamwork : Helps other developers quickly understand your ideas and structure.
If you write a large piece of code without comments, you may have to "read" again after a few months to figure out which piece is for what.
Basic writing of HTML comments
The syntax of HTML comments is very simple, the format is:

<!-- This is a comment-->
You can write any instructions in the middle, or even include HTML code snippets (although it won't be executed).
Several common writing methods:
- Simple explanation:
<!-- This is the header of the page-->
- Tag blocks:
<!-- Start of the main content--> <div class="content">...</div> <!-- End of the subject content-->
- Temporarily disable the code:
<!-- <p>This text does not need to be displayed for the time being</p> -->
Be careful not to nest comments, that is, you cannot add
<!-- ... -->
in a comment, otherwise it may lead to parsing errors.
Some practical tips when using comments
- Don't over-annotate : commenting on each label will interfere with reading. Focus on annotating structural and logically complex parts.
- Stay updated : If the code is modified, remember to update the comment content simultaneously, otherwise it will be misleading.
- Unified style : For example, use Chinese or English uniformly, and the indentation method is consistent, which makes it look more professional and easier to maintain.
- Avoid sensitive information : Some developers will write some internal instructions in comments, but be careful not to leave sensitive content such as passwords and paths in the online code.
Basically that's it. Although HTML comments are inconspicuous, they are indeed a small and practical tool when organizing and maintaining code.
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