Each attribute belongs to a category. And for some types, their values are restricted. Here are the categories of attributes:
<a> attribute "id" has invalid value "567" The attribute ID is of type ID. As described above, it should begin with a letter and have no spaces
![]() | <a id="567" href="/index.html"> |
![]() | <a id="n567" href="/index.html"> |
<img> attribute "width" has invalid value "740px" HTML width and height attributes do not need "px"; their units are always assumed to be pixels.
![]() | <img src="example.png" alt="Example" width="740px" height="40px" /> |
![]() | <img src="example.png" alt="Example" width="740" height="40" /> |
To find the type of the attribute, search the tag name (here) and check its definition.