Can I add a custom attribute to an HTML tag?

custom-attribute, html

Solution

You can amend your !DOCTYPE declaration (i.e. DTD) to allow it, so that the [XML] document will still be valid:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
[
  <!ATTLIST tag myAttri CDATA #IMPLIED>
]>

`#IMPLIED` means it is an optional attribute, or you could use `#REQUIRED`, etc.

More information is in DTD - Attributes.

Problem

Can I add a custom attribute to an HTML tag like the following? ``` <tag myAttri="myVal" /> ```

Original source

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