# The Website Specification > A platform-agnostic, full specification of the technical features a good website should have. Built in the open under an MIT licence. Source: https://specification.website · Repository: https://github.com/jdevalk/specification.website · Content licence: CC BY 4.0 --- # Foundations The HTML, head, and document basics every page needs. ## The HTML doctype Status: required · Source page: https://specification.website/spec/foundations/doctype/ Every HTML document must start with as its first line. This opts the browser into standards mode; without it, you get quirks mode and broken layout. ## What it is The doctype is a short declaration at the very top of an HTML document that tells the browser which rendering mode to use. In modern HTML, there is exactly one correct form: ```html ``` It is case-insensitive, so `` is equally valid. It must be the first thing in the document, before ``, with no whitespace, comments, or byte-order mark trickery in front of it. Despite how it looks, the doctype does not declare a version of HTML. The old `HTML 4.01 Transitional` and `XHTML 1.0 Strict` doctypes pointed at a DTD, so reading them as "this document is written in that version" was fair. `` carries no version and switches on no "HTML5 mode". The modern elements and features you may use do not depend on it: `
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