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  5. <base>

<base> HTML document base URL element

Baseline
Widely available
*

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

* Some parts of this feature may have varying levels of support.

The <base> HTML element specifies the base URL to use for all relative URLs in a document. There can be only one <base> element in a document.

A document's used base URL can be accessed by scripts with Node.baseURI. If the document has no <base> elements, then baseURI defaults to location.href.

Attributes

This element's attributes include the global attributes.

Warning: A <base> element must have an href attribute, a target attribute, or both. If at least one of these attributes are specified, the <base> element must come before other elements with attribute values that are URLs, such as a <link>'s href attribute.

href

The base URL to be used throughout the document for relative URLs. Absolute and relative URLs are allowed. data: and javascript: URLs are not allowed.

target

A keyword or author-defined name of the default browsing context to show the results of navigation from <a>, <area>, or <form> elements without explicit target attributes. The following keywords have special meanings:

  • _self (default): Show the result in the current browsing context.
  • _blank: Show the result in a new, unnamed browsing context.
  • _parent: Show the result in the parent browsing context of the current one, if the current page is inside a frame. If there is no parent, acts the same as _self.
  • _top: Show the result in the topmost browsing context (the browsing context that is an ancestor of the current one and has no parent). If there is no parent, acts the same as _self.

Usage notes