selfclose

Selfclose, or self-close, refers to the syntax used in markup languages to denote an empty element that contains no content. It is commonly written as a self-closing tag, for example <tag/> in which the slash indicates the element has no inner content.

In XML and XHTML, empty elements are typically expressed with the self-closing form. Typical examples include <img src="..." alt="..."/> and <br/>. In these contexts, the self-closing syntax is the standard way to declare an element that does not require a closing tag.

In HTML, the concept exists as void elements—tags that inherently do not have or require content, such as <img>, <br>, <hr>, and <input>. In HTML5, these elements do not require a closing tag and may be written with or without a trailing slash. The slash form is primarily useful for XHTML compatibility or for tools that assume XML-style syntax. For non-void elements (like <div> or <span>), self-closing them with a syntax like <div/> is discouraged in standard HTML and can lead to parsing inconsistencies across browsers.

Usage and compatibility considerations vary by context. In XHTML or XML-based workflows, self-closing syntax is standard for empty elements. In HTML5, while the slash is allowed in start tags, it is generally ignored, and authors are encouraged to use the traditional start tags paired with appropriate content. Validators may flag non-void elements written as self-closing in certain HTML contexts.

See also: HTML, XML, XHTML, SGML, void elements, empty-element tag.