<base>Baseline · Widely available
The <base> element sets the base URL (the URL that relative URLs are relative to) for all relative URLs in the document.
Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Jul 29, 2015. Widely available since Jan 29, 2018.
Browser support
DesktopChrome
1+Supportedsince Dec 11, 2008
Current: 155Edge
12+Supportedsince Jul 29, 2015
Current: 154Firefox
1+Supportedsince Nov 9, 2004
Current: 157Safari
1–2Not supported
3+Supportedsince Oct 26, 2007
Current: 27MobileChrome Android
18+Supportedsince Jun 27, 2012
Current: 155Firefox Android
4+Supportedsince Mar 29, 2011
Current: 157Safari iOS
1–1Not supported
2+Supportedsince Jul 11, 2008
Current: 27How to use
This feature is Baseline widely available — use it freely, no fallback needed.
Example
Full syntax and examples are on MDN: HTMLBaseElement.
Feature detection
JS · check before using
const el = document.createElement("base");
if (!(el instanceof HTMLUnknownElement)) {
// <base> is supported
}Documentation (MDN)
Specification
Sub-features
Support for each part of the feature (8). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| HTMLBaseElement | 1 | 12 | 1 | 3 | 18 | 4 | 1 |
| HTMLBaseElement.href | 1 | 12 | 1 | 3 | 18 | 4 | 1 |
| HTMLBaseElement.target | 1 | 12 | 1 | 3 | 18 | 4 | 1 |
| base | 1 | 12 | 1 | 3 | 18 | 4 | 2 |
| base.href | 1 | 12 | 1 | 3 | 18 | 4 | 2 |
| base.href.forbid_data_javascript_urls | 58 | 79 | 127 | 13.1 | 58 | 127 | 13.4 |
| base.href.relative_url | 1 | 12 | 4 | 3 | 18 | 4 | 2 |
| base.target | 1 | 12 | 1 | 3 | 18 | 4 | 2 |