Head and body tags
A web page is contained between the opening <html> and closing </html> tags.
<html> element
This element contains the whole HTML document. HTML document should have one opening <html> tag and document should end with a closing </html> tag. It has <head> and <body> tags in it.
<head> element
It is the head of the page, having information about the page but not the content of the page as it contain a title and a description of the page, or location for CSS and JavaScript files. The element has an opening <head> tag, the closing </head> tag, and everything in between.
<body> element
It is the body of the web page and has all the content seen on the web page. It consists of the opening <body> tag, closing </body> tag, and everything in between. Usually it appears after <head> element and the contents in it are also called as body content. It can have some paragraphs or complicated layouts having forms and tables for example
<body>
<p>This is a paragraph tag.</p>
</body>
Nesting
An element containing other elements, must wholly contain that element. This is called as nesting elements correctly.
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