HTML <base> Tag

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The <base> tag has recently become part of HTML5. It defines an absolute (base) URL for all the relative URLs in the HTML document. This tag also determines how links in the current document must be opened (in a new window, in the current window, etc.).

You can access the used base URL of a document from scripts with document.baseURI. If the document doesn’t contain any <base> element, baseURL will default to document.location.href.

Syntax

The <base> tag is empty, which means that the closing tag isn’t required. But in XHTML, the (<base>) tag must be closed (<base/>).

Only one <base> tag can be used on the page, and it must be placed in the <head> element. You must insert it as soon as possible since its action extends from the place where it is specified.

If you use multiple <base> elements, only the first href and target attributes will be obeyed. The rest will be ignored.

Example of the HTML <base> tag:

<!DOCTYPE html>
<html>
  <head>
    <title>HTML base tag</title>
    <base href="https://www.w3docs.com/" target="_blank">
  </head>
  <body>
    <a href="/css3-maker/border-radius">Try CSS Maker Tool</a>
  </body>
</html>

Try it Yourself »

Result

In this example, the <base> tag defines the base URL - "https://www.w3docs.com/", and the relative link "/css3-maker/border-radius" will use that URL as a starting point.

Copy the above-mentioned code into our editor, and you will see an active link, which, when clicked, opens in a new window. Although the link itself does not contain the target _blank attribute, it will open in a new window, since we have set the target _blank attribute to the absolute URL in the <base> tag.

Attributes

The <base> tag must necessarily contain either href or target attribute. If necessary, you can use both attributes.

Attribute	Value	Definition
href	URL	Specifies the base URL for all relative URLs of the page. The default base address is substituted before all relative addresses on the page.
target	_blank	Opens the link in a new window.
	_self	Opens the link in the current window.
	_parent	Opens the link in the parent frame.
	_top	Opens the document in the full width of the page.