HTML Checking for Large Sites

The <table> element does not accept a height attribute. Use CSS instead.

The width and height attributes on <img> elements expect a digit to specify the dimension in pixels. It should not contain units, letters or percent signs.

You can achieve this using CSS instead, for example:

<!-- Invalid syntax, the height attribute expects only digits -->
<img src="photo.jpg" alt="cat" height="auto" />

<!-- Valid syntax using CSS -->
<img src="photo.jpg" alt="cat" style="height: auto"  />

Learn more:

• MDN: the img element

The attributes width and height of <img> elements expect a non-negative integer, so an empty string is not allowed. Either define the correct dimension, or remove this attribute.

Learn more:

• HTML Spec: images

The <iframe> element, used to embed another document inside the current document, accepts both attributes width and height which must be valid non-negative integers. Percentages are not allowed for these attributes.

Check the iframe spec.

The attributes width and height on <img> elements define the dimensions of the image in CSS pixels, and expect a non-negative integer.

Learn more:

• HTML Spec: dimension attributes

The width and height attributes on <img> and <iframe> elements expect a digit to indicate the number of pixels. Ensure that this attribute contains only digits.

For example:

<!-- This is invalid because width is not a digit -->
<img width="225px" height="100px" alt="cat" src="cat.jpg" />

<!-- This is valid -->
<img width="225" height="100" alt="cat" src="cat.jpg" />