--- title: "Site - Glossary | MDN" chunk: 1/3 source: "https://developer.mozilla.org/en-US/docs/Glossary/Site" category: "reference" tags: "web, html, css, javascript, documentation" date_saved: "2026-05-05T05:45:23.953476+00:00" instance: "kb-cron" --- * [Skip to main content](https://developer.mozilla.org/en-US/docs/Glossary/Site#content) * [Skip to search](https://developer.mozilla.org/en-US/docs/Glossary/Site#search) [ MDN ](https://developer.mozilla.org/en-US/) HTML [HTML: Markup language](https://developer.mozilla.org/en-US/docs/Web/HTML) HTML reference * [Elements](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements) * [Global attributes](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Global_attributes) * [Attributes](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Attributes) * [See all…](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference "See all HTML references") HTML guides * [Responsive 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[Box-shadow generator](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Backgrounds_and_borders/Box-shadow_generator) * [Color format converter](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Colors/Color_format_converter) * [Color mixer](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Colors/Color_mixer) * [Shape generator](https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Shapes/Shape_generator) About Get to know MDN better * [About MDN](https://developer.mozilla.org/en-US/about) * [Advertise with us](https://developer.mozilla.org/en-US/advertising) * [Community](https://developer.mozilla.org/en-US/community) * [MDN on GitHub](https://github.com/mdn) [Blog](https://developer.mozilla.org/en-US/blog/) 1. [Glossary](https://developer.mozilla.org/en-US/docs/Glossary) 2. [Site](https://developer.mozilla.org/en-US/docs/Glossary/Site) # Site Informally, a _site_ is a website, which is a collection of web pages, served from the same domain and maintained by a single organization, defined by its [registrable domain](https://developer.mozilla.org/en-US/docs/Glossary/Registrable_domain). Browsers sometimes need to distinguish precisely between different sites. For example, the browser must only send [`SameSite`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Set-Cookie#samesitesamesite-value) cookies to the same site that set them. For this more precise definition a site is determined by the _registrable domain_ portion of the domain name. The registrable domain consists of an entry in the [Public Suffix List](https://publicsuffix.org/list/) plus the portion of the domain name just before it. This means that, for example, `theguardian.co.uk`, `sussex.ac.uk`, and `bookshop.org` are all registrable domains. According to this definition, `support.mozilla.org` and `developer.mozilla.org` are part of the same site, because `mozilla.org` is a registrable domain. In some contexts, the scheme is also considered when differentiating sites. This would make `http://vpl.ca` and `https://vpl.ca` different sites. Including the scheme prevents an insecure (HTTP) site from being treated as the same site as a secure (HTTPS) site. A definition that considers the scheme is sometimes called a _schemeful same-site_. This stricter definition is applied in the rules for handling [`SameSite`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Set-Cookie#samesitesamesite-value) cookies. **Note:** Browsers sometimes make security decisions (for example, deciding which resources a script can access) based on the [Origin](https://developer.mozilla.org/en-US/docs/Glossary/Origin) of a resource. This is a more restrictive concept than the site, encompassing the scheme, the whole domain, and the port. See also [same-origin policy](https://developer.mozilla.org/en-US/docs/Web/Security/Defenses/Same-origin_policy). ## In this article * [Examples](https://developer.mozilla.org/en-US/docs/Glossary/Site#examples) * [See also](https://developer.mozilla.org/en-US/docs/Glossary/Site#see_also) ## [Examples](https://developer.mozilla.org/en-US/docs/Glossary/Site#examples) These are the same site because the registrable domain of `mozilla.org` is the same: * `https://developer.mozilla.org/en-US/docs/` * `https://support.mozilla.org/en-US/` These are considered the same site because the port number is ignored when determining the site: * `https://example.com:8080` * `https://example.com` These are not the same site because the registrable domain of the two URLs differs: * `https://developer.mozilla.org/en-US/docs/` * `https://example.com` These are the same site, or different sites if the scheme is considered: * `http://example.com` * `https://example.com` ## [See also](https://developer.mozilla.org/en-US/docs/Glossary/Site#see_also) * [What is a URL](https://developer.mozilla.org/en-US/docs/Learn_web_development/Howto/Web_mechanics/What_is_a_URL) * Related glossary terms: * [Origin](https://developer.mozilla.org/en-US/docs/Glossary/Origin) * [Registrable domain](https://developer.mozilla.org/en-US/docs/Glossary/Registrable_domain) * [Same-origin policy](https://developer.mozilla.org/en-US/docs/Web/Security/Defenses/Same-origin_policy)