Aloitustagi

Aloinestagi, known in English as a start tag, is a markup construct that marks the opening of an element in languages such as HTML and XML. It appears at the beginning of an element’s content and is written inside angle brackets, containing the element name and optional attributes. For example, the start tag for a paragraph might look like <p class="intro">.

The start tag is paired with a matching end tag in many languages. The end tag typically appears after the element’s content and is written as </elementName>. Some elements, called void or self-closing elements, do not require a separate end tag and may be written as <br> or <img src="..."/> in certain syntaxes. In XML, all elements must be properly closed, either with a separate end tag or as a self-closing tag, whereas HTML5 permits some elements to omit the end tag and relies on the parser to infer structure.

In HTML, start tags may be case-insensitive and can include multiple attributes with quoted values. In XML, tag and attribute names are case-sensitive, and attributes must be properly quoted. The correct pairing and nesting of start tags, end tags, and content is essential for well-formed markup and correct rendering by parsers and browsers.

Etymology traces the term to the idea of “tagging” or marking the start of an element. The concept is fundamental across markup languages and contrasts with end tags, which explicitly close elements, and with self-closing tags, which combine opening and closing into a single tag.