HTML Guide
The <table> element does not accept a height attribute. Use CSS instead.
Last reviewed: October 27, 2022
Related W3C validator issues
The height property in your CSS containing invalid or too many values. The height property should have only one valid length, percentage, or keyword value.
Valid Values for height Property:
- Length values: px, em, rem, etc. (e.g., 100px, 10em)
- Percentage values: (e.g., 50%)
- Keyword values: auto, max-content, min-content, fit-content, inherit, initial, unset
Example of Incorrect Usage:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.example {
height: 100px 50px; /* Incorrect: Too many values */
}
</style>
<title>Height Property Example</title>
</head>
<body>
<div class="example">Content</div>
</body>
</html>Example of Correct Usage:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.example {
height: 100px; /* Correct: One valid value */
}
</style>
<title>Height Property Example</title>
</head>
<body>
<div class="example">Content</div>
</body>
</html>Both <table> and <td> elements no longer accept a width attribute. Instead, you should use CSS as in this example:
<table style="width:100%;">
<tr>
<td style="width:50px;">Name</td>
</tr>
</table>Table rows on the same <table> element must have the same number of columns, which comes determined by the first tr row.
For example, this table is wrong as the first row defines 2 columns, while the second row tries to use 4 columns:
<table>
<tr>
<td>Liza</td>
</tr>
<tr>
<td>Jimmy</td>
<td>14</td>
</tr>
</table>A <table> contains a <tr> row that has less <td> columns than the column count established by the first row. Check the table to ensure all rows have the same number of columns.
For example, in the following table, the first <tr> row defines that it’s 2 columns wide, but the second <tr> row tries to use only 1 column:
<table>
<!-- This first row sets the table as 2 columns wide -->
<tr>
<td>First</td>
<td>Second</td>
</tr>
<!-- This second row has only 1 column -->
<tr>
<td>Wrong</td>
</tr>
</table>The attribute displayText is not allowed on <span> elements.
This issue is commonly caused by an old integration of ShareThis via Drupal or other CMS - the old code used invalid attributes like displayText, st_url and st_title which were later changed to HTML5 custom data attributes.
Check the syntax of the affected tag, it’s probably malformed and a < character inside has been interpreted as an attribute.
For example, this code might cause this issue:
<!-- Malformed img tag -->
<img src="photo.jpg" alt="smiling cat" < />
<!-- Fixed img tag -->
<img src="photo.jpg" alt="smiling cat" />The attribute st_title is not allowed on <span> elements.
This issue is commonly caused by an old integration of ShareThis via Drupal or other CMS - the old code used invalid attributes like displayText, st_url and st_title which were later changed to HTML5 custom data attributes.
The attribute st_url is not allowed on <span> elements.
This issue is commonly caused by an old integration of ShareThis via Drupal or other CMS - the old code used invalid attributes like displayText, st_url and st_title which were later changed to HTML5 custom data attributes.
An invalid attribute has been found on an element. Check the affected tag to ensure attributes are well-formed, and if they are you can consider using custom data attributes.
The xmlns:dt attribute is not permitted on standard HTML elements according to the HTML specification.
HTML5 does not use XML namespaces like xmlns:dt, which are only valid in certain XML vocabularies such as XHTML or when embedding MathML or SVG. In typical HTML, attributes with xmlns or any custom XML namespace prefixes are invalid and cause validation errors.
To fix this issue, simply remove the xmlns:dt attribute from your HTML tags.
If you are using a data attribute or a custom attribute, you can use data-* attributes instead, which are allowed in HTML5.
Incorrect usage with xmlns:dt:
<div xmlns:dt="urn:schemas-microsoft-com:datatypes">
Content here
</div>Correct usage—attribute removed:
<div>
Content here
</div>If you need to store custom data, use data-* attributes:
<div data-dt="urn:schemas-microsoft-com:datatypes">
Content here
</div>Avoid using XML namespaces in HTML5 documents to ensure your code is standards-compliant.