HTML
Doctype Declarations - First thing in the page, yet often overlooked.
Saturday, August 16th, 2008 | HTML | No Comments
Considering this is my first post, i thought what better way to start than with the first element on a typical html page, the doctype declaration (usually referred to as the shorthand ‘DOCTYPE’). Most designers and developers would admit to simply cutting and pasting this crucial snippet of code from an external source without understanding its true meaning or purpose. It is beneficial to have a basic understanding of the DOCTYPE because it can be the source of rendering issues and is often the last place you would look to rectify a problem. A DOCTYPE essentially informs the browser as to which Document Type Definition (DTD) you intend your markup to conform to. A DTD being a specification of the rules and guidelines as to the structure of the markup you write.
DOCTYPE options
In terms of web standards, a DOCTYPE informs the validator which version of (X)HTML you’ve incorporated, and must appear at the top of every page. DOCTYPEs are an essential component of standards compliant web pages: your markup and CSS will simply not validate without them.
In fact, using an incorrect/incomplete DOCTYPE - or no DOCTYPE at all - leads many browsers to render your page in a so-called “Quirks” mode. Essentially, in this event the browser assumes that you’ve written outdated, invalid markup characteristic of the late 90s. To cope with this, the browser will try to render your website in a backward-compatible mode, displaying it as it might have appeared in antiquated browsers such as IE4. This is usually not what you intend and will result in all kinds of problems.