Which doctype to choose

As a web designer or developer, you will get the most consistent results by making sure that all browsers use their Standards rendering mode, hence you should stick to web standards, and use a proper doctype! As I mentioned earlier, the doctype is also used by validators, which you will learn more about later in this article series. For now, all you need to know is that a validator is used to check that the syntax of your HTML document is correct and does not contain any mistakes.

The validator programs look at the doctype you have used to determine what rules to use. So, now that you know that you need to insert a doctype and what it is used for, how will you know which one to choose? You could even create your own if you feel up to something more advanced.

Note: "Real" XHTML should be delivered to the web browser as XML, but the details of how and when to do that, and the implications it has, is beyond the scope of this particular article. Both of these doctypes will ensure that browsers use their Standards mode when dealing with your document. We'll never sell or share your email address! Read our Privacy Policy. Blog We love to talk! Mar Mon. Web Development. Get your website Internet Explorer 10 ready.

These modes were incompatible with existing Web content and were abandoned. It does not. Only documents served using an XML content type e. Although the Quirks mode is primarily about CSS, there are some scripting quirks as well. In Firefox, document. The effects on scripting are more dramatic in IE when falling into a mode that emulates an old version of IE.

With hindsight, this is quite unfortunate. This means that the mode is picked based on the document type declaration or the lack thereof at the beginning of an HTML document. This does not apply to documents served with an XML content type. In the HTML 4. More on this in the addendum. Neither the HTML 4. The document type declaration is placed in the document before the start tag of the root element.

This is what you should use. Please be sure to test your page in the latest versions of the top browsers. This gives you the Almost Standards mode. Willfully designing for the Quirks mode will come and haunt you, your coworkers or your successors in the future.

If you frustrated by the differences between old IE versions and still need to support them due to client requirements, it is better to apply specific hacks for legacy versions using conditional comments than seek commonality in the Quirks mode. Please see the Addendum below. It was announced on A List Apart that IE8 would use a meta element-based mode switch in addition to doctype being a factor in the mode choice. IE8 has four modes: IE 5.

IE9 has seven modes: IE 5. IE10 has eleven modes: IE 5. The choice of mode depends on data from various sources: doctype, a meta element, an HTTP header, periodically downloaded data from Microsoft, the intranet zone, settings made by the user, settings made by an intranet administrator, the mode of the frame parent if any and a UI button togglable by the user.

With other apps that embed the engine, the mode also depends on the embedding application. Your interactions with this site are in accordance with our public and Member privacy statements.

Recommended list of Doctype declarations. Warning The list is informative and does not try to be exhaustive there are many other proper declarations you could use , but it has most of the declarations commonly used on the Web at the moment.