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

The HTML specification defines the height and width attributes on the <embed> element as valid non-negative integers. This means the value must consist only of digits — for example, 650 — with no units, whitespace, or other characters appended. When you write height="650px", the validator encounters the letter “p” where it expects either another digit or the end of the value, and it raises this error.

This is a common mistake because CSS requires units (e.g., 650px), and it’s easy to assume HTML attributes work the same way. They don’t. In HTML, the height attribute implicitly means CSS pixels, so writing 650 already means “650 pixels.” Adding px is not only redundant — it makes the value invalid.

While most browsers are forgiving and will parse 650px correctly by stripping the unit, relying on this behavior is problematic. It violates the HTML specification, causes validation errors that can mask other real issues in your markup, and there’s no guarantee every browser or embedded content handler will be equally tolerant. Standards compliance ensures consistent rendering across browsers and assistive technologies.

How to fix it

You have two approaches:

1. Remove the unit from the HTML attribute. Change height="650px" to height="650". This is the simplest fix and keeps your sizing in the markup.

2. Move sizing to CSS. Remove the height attribute entirely and use a stylesheet or inline style attribute instead. This approach is more flexible because CSS supports units like %, em, vh, and more.

The same rule applies to the width attribute on <embed>, as well as height and width on elements like <img>, <video>, <iframe>, and <canvas> — all of which expect plain integers in HTML.

Examples

❌ Invalid: unit included in the HTML attribute

The px suffix causes the validator error because the attribute value must be digits only.

<embed src="file.pdf" type="application/pdf" width="800" height="650px">

Other invalid variations include:

<embed src="file.pdf" type="application/pdf" height="100%">
<embed src="file.pdf" type="application/pdf" height="40em">
<embed src="file.pdf" type="application/pdf" height="50vh">

✅ Fixed: plain integer without a unit

Remove the unit so the value is a valid non-negative integer.

<embed src="file.pdf" type="application/pdf" width="800" height="650">

✅ Fixed: sizing moved to CSS

If you need units other than pixels, or prefer to keep presentation in your stylesheets, use CSS instead of the HTML attribute.

<embed class="pdf-viewer" src="file.pdf" type="application/pdf">

.pdf-viewer {
  width: 800px;
  height: 650px;
}

✅ Fixed: inline style as an alternative

You can also use the style attribute directly if a separate stylesheet isn’t practical.

<embed src="file.pdf" type="application/pdf" style="width: 800px; height: 80vh;">

This is especially useful when you need viewport-relative or percentage-based sizing that HTML attributes can’t express.

Learn more:

MDN Reference

<embed> - HTML: HyperText Markup Language | MDN

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WHATWG Spec

HTML Living Standard: The embed element

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MDN Reference

MDN: CSS height

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