HTML Guide
In the days before HTML5, named anchors were used as a way to provide a link to a specific section of a document, for example:
<h2>
<a name="section-5">Section 5</a>
</h2>
Now in HTML5, the name attribute is obsolete for <a> tags, and instead, you can use the id attribute of any element (not just <a>) as a way to navigate directly to it, for example:
<h2 id="section-5">Section 5</h2>Learn more:
Related W3C validator issues
The <option> element no longer accepts a name attribute, which is now obsolete.
Example:
<select id="pet-select">
<option value="">--Please choose an option--</option>
<option value="dog">Dog</option>
<option value="cat">Cat</option>
<option value="hamster">Hamster</option>
</select>The id attribute of an HTML element, used to identify the element when linking, scripting or styling, must be unique in the whole document and must not contain whitespace.
Technically, in HTML5, the value for an id attribute may contain any character, except whitespace characters. However, to avoid inadvertent errors, only ASCII letters, digits, _, and - should be used and the value for an id attribute should start with a letter.
A <meta> tag has been found that is either malformed, or in a bad place within the document. Check its attributes and context.
For example, the following HTML contains a valid <meta> tag that is raising an issue because of bad context, caused by an <img> tag that shouldn’t be there:
<!DOCTYPE html>
<html lang="">
<head>
<title>Test</title>
<img src="photo.jpg" alt="A smiling cat" />
<meta name="description" content="Description of this page" />
</head>
<body>
<p>Some content</p>
</body>
</html>If we fix that document and move the <img> tag within the body, the issue raised about <meta> disappears because it’s now in a valid context:
<!DOCTYPE html>
<html lang="">
<head>
<title>Test</title>
<meta name="description" content="Description of this page" />
</head>
<body>
<p>Some content</p>
<img src="photo.jpg" alt="A smiling cat" />
</body>
</html>The for attribute on a label element can’t be an empty string. This attribute is intended to specify which form element a label is associated with, and it must reference the ID of an existing form element. An empty string is neither a valid ID nor a meaningful association.
Explanation
- Invalid HTML: <label for=""></label>
The for attribute expects the value to be the ID of a form element, such as an input, textarea, select, etc.
How to Fix
- Identify the Form Element: Find the form element (input, textarea, select, etc.) that the label is supposed to be associated with.
- Assign an ID to the Form Element: Ensure the form element has a unique ID.
- Modify the Label’s for Attribute: Set the for attribute of the label to match the ID of the form element.
Example
Before Fix
<form>
<label for="">Username:</label>
<input type="text" name="username">
</form>After Fix
<form>
<label for="username">Username:</label>
<input type="text" id="username" name="username">
</form>The id attribute is used to identify a single element within a document, it’s not required, but if used it must be unique, and must not be an empty string.
IDs for HTML elements can’t be blank.
The name attribute is required for all input elements.
The <label> element represents a caption in a document, and it can be associated with a form input using the for attribute, which must be an ID. Document IDs cannot contain whitespace.
Example:
<form>
<label for="user_name">Name</label>
<input type="text" id="user_name" />
</form>A <pattern> element has been found with an invalid ID. Check the format of the ID and ensure it does not start with a digit, full stop (.) or hyphen (-).
The <pattern> element is used within <svg> elements, which use XML 1.0 syntax. That syntax specifies that valid IDs only include designated characters (letters, digits, and a few punctuation marks), and do not start with a digit, a full stop (.) character, or a hyphen-minus (-) character.
The value of the name attribute on an <iframe> should not start with an underscore (_).
Browsing context names that begin with an underscore are reserved keywords in HTML, like _blank, _self, _parent, and _top. Using these reserved names or any custom name starting with an underscore for the name attribute of an <iframe> can lead to unexpected behavior and is considered invalid HTML.
Here’s how to fix the issue:
Problematic Code
<iframe src="https://example.com" name="_example"></iframe>Solution
To resolve this issue, you should use a valid value for the name attribute that does not start with an underscore.
Corrected Code
<iframe src="https://example.com" name="example"></iframe>Steps:
- Identify the iframe element with the invalid name attribute value that starts with an underscore.
- Replace the name value with a valid identifier that does not start with _. Use letters, numbers, hyphens (-), and underscores (_) (but not at the beginning).