The steps to verify HTML5 code normativeness include checking using tools such as W3C Markup Validation Service. 1. Open the W3C validator and enter the web page URL or paste the source code; 2. Click the "Check" button to start verification; 3. Check the error and warning content in the report and repair it item by item; 4. Based on the actual situation, determine whether to handle non-fatal errors; 5. Upload HTML files for verification during local development. Common errors include unclosed labels, discarded labels, unquoted attribute values, irregular custom attributes, and element nesting errors, which can be modified one by one according to the prompts.
Verifying whether the HTML5 code is standardized is an easy to ignore but very important link in front-end development. Although modern browsers are highly fault-tolerant to irregular HTML, maintaining a good markup structure can help improve page compatibility, SEO performance, and post-maintenance efficiency. Using online tools and verification services, you can quickly detect and fix syntax errors or irregular writing methods in your code.
Find a reliable HTML verification tool
The most authoritative HTML validator at present is the W3C Markup Validation Service , which is maintained by the World Wide Web Consortium (W3C), supports HTML5, and can accurately identify most common syntax problems. In addition to W3C, there are some other practical tools, such as:
- HTML Validator (Chrome plug-in) : Suitable for developers to check pages in real time.
- Nu Html Checker : Based on command line or local deployment, suitable for integration into the development process.
- Third-party websites such as Online HTML Validator : convenient and fast, suitable for temporary inspection.
It is recommended to give priority to the use of W3C's online verification service because it is timely updated and has clear standards.
How to use online tools to verify HTML pages
Using online verification tools is actually very simple. Taking W3C as an example, the operation steps are as follows:
- Open the W3C Verifier
- Enter the web page URL or paste the HTML source code directly
- Click the "Check" button to start verification
- View error and warning content in the report and fix it item by item
Sometimes you will see some warnings that are not fatal errors, such as false positives for certain custom properties such as data-*. At this time, we need to determine whether it needs to be handled based on the actual situation.
In addition, if you are developing locally and not online yet, you can upload and verify HTML files directly. Many tools support file upload function.
Common HTML5 verification errors and solutions
In actual use, common verification errors include:
- The tag is not closed, such as
<div> no corresponding <code>
<center></center> and <font></font>
class=myClass
<a></a> in the <a></a> tagWhen encountering these problems, you can modify the code according to the specific prompts given by the validator. For example, if the prompt "Stray start tag", it means that a tag may be placed in the wrong position or is not closed correctly; if it is "Attribute not allowed", it may be that you used an illegal attribute or a misspelling.
Some editors (such as VS Code) can also prompt these errors in real time when writing code, and find problems in advance.
Basically that's it. HTML verification is not a necessary hard requirement, but it can indeed help us avoid many potential problems in the process of building high-quality web pages. The tools are not complicated, the key is to develop the habit of checking.
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