HTML Guide

The media attribute on the link element cannot use the deprecated value projection; only valid CSS media types should be specified.

The media attribute specifies what media/device the linked resource is designed for, using a media query or a list of valid media types. In modern HTML and CSS, commonly accepted values include all, print, and screen.

The value projection was intended for projectors but has been deprecated and is no longer recognized by browsers or the HTML standard. To ensure validity and compatibility, remove projection and use only accepted types such as screen and/or print.

Incorrect example (with deprecated value):

<link rel="stylesheet" href="style.css" media="screen, projection">

Correct examples:

<link rel="stylesheet" href="style.css" media="screen">

<link rel="stylesheet" href="style.css" media="screen, print">

If you intend your stylesheet for screens and print, you can use both screen, print; for only screens, use just screen. If the stylesheet should apply to all devices, you can omit the media attribute or use all:

<link rel="stylesheet" href="style.css">

or

<link rel="stylesheet" href="style.css" media="all">

The deprecated property longdesc on img elements was used in HTML4 to specify the URL of a text or HTML file which contained a long-form description of the image. This could be used to provide optional added details beyond the short description provided in the title or alt attributes.

Here’s an example from HTML4:

<img
  src="cat.jpg"
  alt="Smiling Cat"
  longdesc="image-descriptions/smiling-cat.html" />

This, however, is no longer valid in HTML5 and can be converted to the following instead:

<a href="image-descriptions/smiling-cat.html">
  <img src="cat.jpg" alt="Smiling Cat" />
</a>