The HTML <base>
element specifies the base URL to use for all relative URLs in a document. There can be only one <base>
element in a document.
The used base URL of a document can be accessed from scripts with document.baseURI
. If the document contains no <base>
elements, baseURI
defaults to document.location.href
.
Content categories | Metadata content. |
---|---|
Permitted content | None, it is an empty element. |
Tag omission | There must be no closing tag. |
Permitted parents | Any <head> that doesn't contain any other <base> element |
Permitted ARIA roles | None |
DOM interface | HTMLBaseElement |
Attributes
This element's attributes include the global attributes.
If either of the following attributes are specified, this element must come before other elements with attributes whose values are URLs, such as <link>
’s href
attribute.
href
- The base URL to be used throughout the document for relative URLs. Absolute and relative URLs are allowed.
target
- A keyword or author-defined name of the default browsing context to display the result when links or forms cause navigation, for
<a>
or<form>
elements without an explicittarget
attribute. The attribute value targets a browsing context (such as a tab, window, or<iframe>
). - The following keywords have special meanings:
_self
: Load the result into the same browsing context as the current one. (This is the default.)_blank
: Load the result into a new, unnamed browsing context._parent
: Load the result into the parent browsing context of the current one. (If the current page is inside a frame.) If there is no parent, behaves the same way as_self
._top
: Load the result into the topmost browsing context (that is, the browsing context that is an ancestor of the current one, and has no parent). If there is no parent, behaves the same way as_self
.
Usage notes
Multiple <base>
elements
If multiple <base>
elements are used, only the first href
and first target
are obeyed — all others are ignored.
In-page anchors
Links pointing to a fragment in the document — e.g. <a href="#some-id">
— are resolved with the <base>
, triggering an HTTP request to the base URL with the fragment attached.
For example, given <base href="https://example.com">
...and this link: <a href="#anchor">Anker</a>
...the link points to https://example.com/#anchor
.
Open Graph
Open Graph tags do not acknowledge <base>
, and should always have full absolute URLs. For example:
<meta property="og:image" content="https://example.com/thumbnail.jpg">
Examples
<base href="https://www.example.com/"> <base target="_blank"> <base target="_top" href="https://example.com/">
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of '<base>' in that specification. |
Living Standard | No change since last snapshot. |
HTML5 The definition of '<base>' in that specification. |
Recommendation | Specified the behavior of target |
HTML 4.01 Specification The definition of '<base>' in that specification. |
Recommendation | Added the target attribute |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
base | Chrome Full support Yes | Edge Full support Yes | Firefox Full support 1 | IE
Full support
Yes
| Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 4 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
href | Chrome Full support Yes | Edge Full support Yes | Firefox Full support 1 | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 4 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
target | Chrome Full support Yes | Edge Full support Yes | Firefox Full support Yes | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
- See implementation notes.
- See implementation notes.