[font="Open Sans", sans-serif]No, the <!DOCTYPE html> declaration is not an HTML tag.[/font]
[font="Open Sans", sans-serif]There are many type of HTML, such as, HTML 4.01 Strict, HTML 4.01 Transitional, HTML 4.01 Frameset, XHTML 1.0 Strict, XHTML 1.0 Transitional, XHTML 1.0 Frameset, XHTML 1.1 etc. So, <!DOCTYPE html> is used to instruct the web browser about the HTML page.[/font]
[font="Open Sans", sans-serif][b]Q21. Why is a URL encoded in HTML?[/b][/font]