HTML <!DOCTYPE> Declaration
<title>Title of the document</title>
The content of the document......
Definition and Usage
All HTML documents must start with a
The declaration is not an HTML tag. It is an "information" to the browser about what document type to expect.
In HTML 5, the declaration is simple:
Older HTML Documents
In older documents (HTML 4 or XHTML), the declaration is more complicated because the declaration must refer to a DTD (Document Type Definition).
HTML元素 and Doctypes
Look at our table of all HTML elements, and what Doctype each element appears in.
Tips and 笔记
<!DOCTYPE> declaration is NOT case sensitive.