How to Set a Web Page's Doctype?
What is a Doctype?
A web page's doctype is an instruction to the browser about which standard to
use for the document. Several doctypes declarations and standards have existed
through the years and you can find a list of them at www.w3.org's website. Since
doctypes and standards have changed over time, the oldest web pages would not
quite look right if rendered by a browser using the most recent standard.
Additionally, newer web pages would not display correctly if the browser applied
an older standard. Typically, browsers have a sets of code based on each
standard that is used to render the content. The doctype declaration is simply a
way to tell the browser which set of code it should use to appropriately render
Why Set a Web Page's Doctype?
Setting a web page's doctype is extremely important. If you do not specify a
doctype, browsers are left to guess the doctype. Granted, browsers are pretty
smart about determining the doctype, but this can result in different problems
such as the layout being messed up or showing elements that are meant to be
hidden as plain text. Without a doctype declaration, browsers will load the page
slower because it has to parse the document to determine the type and then start
rendering the web page. If it cannot determine the type, then it launches into a
"quirks" mode to render the web page's content. Setting the doctype aids
browsers by telling them the standard you are using on this page and prevents
them from using "quirks" mode to show your document.
Setting the Doctype
If you are using an environment like DreamWeaver, the doctype was probably
included for you. A doctype is always specified before the HTML tag so that the
browser understands the standard before it parses the content. Here are some
examples of doctype declarations.
HTML 4.01 Doctype Declaration
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
HTML 5 Doctype Declaration
What is SEO Analysis?
Open Graph Protocol
What is DMOZ?
How to build Backlinks?
How to Use the Canonical Tag?
What is a Web Page Description?
What is a Doctype?
What is an Encoding Type?
What is the Alt Attribute of an Image?
What are Meta Keywords?
Why Improve a Website's Page Speed?
What is Profanity?
Social Sharing Options
Right Text Length for a Web Page
What is a Page Title?
Why Increase Website Traffic?
Why Rewrite Your URLs?
Why Remove Underscores?
What is the WWW Resolve?