| Glossary of Terms
What is DocType?
What is a DocType? Ever been leery of asking silly questions like - what is a DocType? No worries, this article attempts to answer that question for you so you don't even have to worry about asking it in privacy.
Doctype declarations shouldn't be reserved as loose, standard written source code that doesn't matter. Faulty doctypes render the ability to validate compliant web pages impossible. Take note, the best system design with the greatest style elements regardless of authoring, tools, text, or use of Document Object Model may not produce valid documents or pages and may experience browser problems, even with older and newer versions of Explorer or Netscape, if the declarations in the doctypes aren't up to standards.
Older versions of Explorer and Netscape render a document in quirk mode while newer versions do their rendering in standard mode. In the absence of doctypes, you'll find the browser switching to quirk instead of standard mode.
Using different doctypes basically affects the way pages are rendered by web browsers which ultimately impacts the performance of the web pages.