The HTML Base Element (<base>) specifies the base URL to use for all relative URLs contained within a document.There is maximum one <base> element in a document.

Usage note: 
If multiple <base> elements are specified, only the first href and first target value are used; all others are ignored.

Content categories:
Metadata content.

Permitted content:
None, it is an empty element.

Tag omission:
There must be no closing tag.

Permitted parent elements:
Any <head> that doesn't contain any other <base> element.

DOM interface:
HTMLBaseElement
