Common verification errors when newbies write HTML5 include unclosed tags, wrong format of self-closed tags, unquoted attribute values, use of discarded tags, and improper use of form attributes. 1. Structural tags such as
When newbies write HTML5, they often cause abnormal page display or report errors in the verification tool due to some minor errors. Below are some common HTML5 verification errors and corresponding solutions, which are basically places that are easy to get stuck when writing code.
The tag is not closed correctly
HTML5 Although not as strict as XHTML requires that all tags must be closed, some tags will still cause parsing problems if they are not closed, especially when using certain frameworks or tools.
- Common Situations:
- Forgot to close the structure tags like
- Forgot to close the structure tags like
<img src="/static/imghw/default1.png" data-src="a.jpg" class="lazy" alt="What are common HTML5 validation errors?" > , <br> ) are written in irregular forms, such as <br> or <img src="/static/imghw/default1.png" data-src="a.jpg" class="lazy" alt="What are common HTML5 validation errors?" >
It is recommended to use standard writing methods in a unified manner, such as:
<img src="/static/imghw/default1.png" data-src="photo.jpg" class="lazy" alt="What are common HTML5 validation errors?"> <br>
Instead of writing in XML style with slashes.
The attribute value is not quoted or the format is incorrect
HTML5 allows attribute values ??to be unquoted, but in actual development, it is safer to add quotes, especially when attribute values ??contain spaces or other special characters.
- Error example:
<input type=email required placeholder=Enter your email>
- Recommended writing method:
<input type="email" required placeholder="Enter your email">
Especially for attributes like class="my-class" or data-* , once there are spaces or special symbols in the value, problems will arise without quotation marks.
Obsolete or discarded tags were used
HTML5 has eliminated some old tags, such as <center> , <font> , <frame> , etc. Although these tags can still be displayed in the browser, they do not meet modern standards and cannot pass the verification check.
- If you see a warning like this:
The center element is obsolete. Use CSS instead.
That means you used a tag that you shouldn't use. Instead of relying on labels with unknown semantics, you should use CSS instead.
The form element is missing the necessary attribute or type error
HTML5 has introduced many new form features, such as type="email" , required , placeholder , etc. However, if used improperly, it will also cause verification failure.
For example, if you want to verify it with your email address, you wrote it:
<input type="text" required>
This loses the role of HTML5 form verification.
The correct way to do it is:
<input type="email" required placeholder="you@example.com">
In addition, if
typeattribute is not specified for<button></button>, it will becomesubmitby default, which can sometimes lead to unexpected form submission, which is also a point to pay attention to.Basically, these common HTML5 verification errors are among the most common HTML5 verification errors. Pay more attention to label structure, attribute format and semantics when writing code, and many problems can be avoided.
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