Though HTML is much easier to learn than building information modelling or duplicating software, you can still run into frustrating problems when you're trying to design your website because you have left out a critical piece of code or even a single punctuation mark. One of the common mistakes newbies make when writing in HTML is failing to define the doctype, which can make the webpage display improperly in certain types of browsers or on old versions of specific browser types. More on doctypes can be found here.
First, what is a doctype? Doctype, which stands for documents type declaration, is the name given to the part of your code which tells the HTML validator in a web browser which type of HTML to use when attempting to read what you have written. It may surprise you to know this, but there is more than one version of HTML floating around out there. Since standard HTML might not be enough to help you design your law office website (example shown), you should know about the others.
The current "versions" of HTML and XHTML are 5 and 1. Some of the different variations of these that you may run across in your quest to create your website include HTML 5.01 Strict, HTML 5.01 Transitional, HTML 5.01 Frameset, XHTML 1.0 Strict, XHTML 1.0 Transitional, and XHTML 1.0 Frameset. If you're worried about an older browser not being able to display the information in your website for a craft shop in Tucson, you may even want to downgrade to HTML 4, 3.2, or even 2.0, which you will need to include as your doctype.
The doctype tag should be the first thing you type into your web design document. If you're doing a simple online brochure style website, simply using or as your opening tag is acceptable depending on which language you're using. However, if you're using one of the above variations of HTML or XHTML, you will need to tell the browser about it by including this information in the doctype.
So what will happen if you fail to declare your doctype? Well, the likely result is that the user's browser will fail to display the website you made. Some information may be displayed, but improperly. This is because the different versions of HTML and XHTML use different tags, some of which overlap. Therefore the browser is reading a tag's meaning in the wrong version or failing to recognize it outright, which results in a mess in your browser window. Always test your page with different versions of different browsers before going live.