Bad value X for attribute “height” on element “object”: Expected a digit but saw “p” instead.

The height attribute of an <object> takes a number of CSS pixels written as digits only, so a unit such as px in height="800px" makes the value invalid.

The HTML standard defines width and height on <object> as dimension attributes, whose value must be a valid non-negative integer. The validator reads the value from the left and stops at the first character that isn't a digit. In 800px that is the p, and pt or pc stop at the same letter. Other units are reported by their first character (v in 80vh, e in 40em). A percentage such as 100% gets its own error, about the % sign.

Browsers read the leading digits and drop the rest, so height="800px" already renders 800 pixels tall. Deleting the unit leaves the layout as it is. The attribute can only express pixels, though. For a height in viewport units, ems or a percentage of the container, remove the attribute and set the CSS height property instead.

Invalid example

<object data="/docs/annual-report.pdf" type="application/pdf" width="600" height="800px"></object>

Valid example

<object data="/docs/annual-report.pdf" type="application/pdf" width="600" height="800"></object>

To size the object relative to the viewport, use CSS:

<object data="/docs/annual-report.pdf" type="application/pdf" style="width: 100%; height: 80vh;"></object>

Learn more:

MDN Reference

MDN Web Docs: The external object element

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WHATWG Spec

HTML Standard: The object element

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MDN Reference

MDN Web Docs: CSS height

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