What happens if you don declare doctype

One should never be in quirks mode and always have a doctype. I'm saying not having a doctype doesn't do what you think it does. It is always recommended to define the doctype at the beginning. This only repeats part of what was stated in the question and, otherwise, doesn't answer the question at all. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta.

Now live: A fully responsive profile. Related Hot Network Questions. Webmasters Stack Exchange works best with JavaScript enabled. Accept all cookies Customize settings. Tigist Mikhnev Professional. What is meant by Dom? It defines the logical structure of documents and the way a document is accessed and manipulated. Gullermo Jubany Professional. What is doctype good for? The doctype is used for two things, by different kinds of software: Web browsers use it to determine which rendering mode they should use more on rendering modes later.

Markup validators look at the doctype to determine which rules they should check the document against more on that later as well. Pop Miguens Explainer. Jincheng Quille Explainer. Such a specification is itself a document type definition DTD. SGML is not in itself a document language, but a description of how to specify one.

Nikolaus Bresges Explainer. What is a semantic tag? This is both semantic and presentational because people know what paragraphs are, and browsers know how to display them. Imeldo Abelman Pundit. What is the correct HTML for inserting an image? Fast Links. What does the issue mean What triggers this issue How to check the issue The importance of the issue How to fix this issue.

Ivan Palii. Site Audit Issues. Asked 7 years, 6 months ago. Active 1 month ago. Viewed 47k times. Improve this question. Usama Abdulrehman 1, 3 3 gold badges 9 9 silver badges 20 20 bronze badges. Maxemoss Maxemoss 1 1 gold badge 2 2 silver badges 11 11 bronze badges. It can, yes. You can end up in browser compatibility modes. How this affects your page depends on what's on it.

You will end up in the dreaded "quirks mode" - a broken and ill-defined place. See Quirks mode and strict mode. Add a comment. Active Oldest Votes. Improve this answer.