What exactly Is XHTML? is it html or xml? it’s a little of both…
Anyone who has even the slightest bit of knowledge about how websites are constructed is aware of the term “HTML”; in fact, the term is tossed around a lot – and is often misused. Regardless, most people understand that the websites they view are created by code, and that HTML is a term that refers roughly to that code. Although this is a very elementary view of the topic, it is used here to demonstrate the fact that of all the markup languages used to create sites on the Internet, HTML has persisted in being the one that most people are familiar with.
Therefore, when the term XHTML is thrown out there, many people do a double take of sorts. We’re not talking about web developers and programmers here; we are referring to everyday users of the Internet. For casual web users, the term XHTML is largely meaningless. Sure, the “HTML” in the name gives a clue that it’s related to the more familiar HTML term, but what does it actually mean?
Explaining what XHTML is used for is impossible without having a firm grasp about what the HTML and XML languages are all about. In this article, we will briefly cover what HTML and XML are in easy to understand terms. From there, we will discuss what XHTML is and its relationship to XML and HTML. We’ll also outline a few useful tips regarding how to use XHTML. By the end of this article, readers should have a decent understanding of what XHTML is.
What Is HTML?
In a nutshell, HTML (HyperText Markup Language) is the primary type of markup language used in creating web pages. It is used to arrange and describe text based information in a document, and to embed other objects within that text as well. With HTML, paragraphs, headings, lists, and other formatting can be applied to a document and then rendered properly by various web browsers. Other attributes like font style, size and positioning can also be specified using HTML. It is important to note here that HTML uses specific tags to render web pages, and that certain tags cannot be rendered by certain browsers.
What Is XML?
XML – or extensible markup language – was basically created to maintain the power and versatility of HTML while making it less complex. HTML depends upon specific and rigid tags to organize the text that one views on a web page; XML essentially defines tags, and serves to define structured information. It is very flexible in that regardless of the content being created, XML can be used to create specific tags for any set of data the user requires. It essentially tells a program how to define the data being presented, allowing it to then be organized in any way.
So, What Is XHTML?
XHTML takes the best attributes of HTML and XML, combining them to allow web developers to create websites that can be rendered correctly by browsers of all kinds. Someone using HTML, for instance, is restricted to working with an immovable set of existing tags; if one doesn’t exist that suits their needs, they are out of luck. Also, if they use less common tags to apply a style to their document, some browsers will be unable to read it properly, making the resulting page appear muddled and unprofessional.
Users working with XML can define the tags that they use; unlike HTML users, they are not restricted to a finite number of tags. With XHTML, one is essentially working within the structure and organization that is so appealing to HTML, but is able to create tags as needed. In other words, in XHTML you can organize a page using HTML; as its being created, you can use XHTML modules to define the markup tags that you need. From there, you can use the tags you’ve created within the document as you would any other HTML tag. Because it is defined via modules within the code, there is no risk of it not being rendered correctly by different browsers; to ensure this, XHTML can be used to define how the content will be rendered by specific browsers.
Basic Things To Keep In Mind When Using XHTML
Although we will not go into how to write entire pages of code using XHTML, we will present some basic tips and guidelines – or rules, if you will – regarding how it is to be written. This can serve as a handy reference guide and can also introduce you to the nature of this markup language. Despite being flexible in terms of defining tags, it is very rigid in terms of how it is written.
- Use all lowercase – All tags written in XHTML must be in lowercase; uppercase letters will cause errors in the document
- End tags are mandatory – Regardless of the type of tag being used, an end tag must be present at all times. Omitting an end tag when using XHTML will cause errors
- Proper nesting is critical – If you are defining multiple attributes using tags – for instance, italicized bold fonts – the italic tag and bold tag must be accompanied by end tags in the reverse order for proper nesting
- Even empty elements must have end tags – Even empty elements like “br” must have end tags. This means you can use the “br” tag, but it must have the “/br” tag as well. Often, people write it simply as “br”,”/br” back to back in order to get around this issue
- Use “id” instead of “name” – For those familiar with HTML, it is important to note that when using XHTML, instances where the “name” attribute would be used would now use the attribute “id”
There is, naturally, a lot more to keep in mind when using XHTML; the preceding was meant to give a basic overview. There’s no question that XHTML has given web developers and programmers a great deal of added flexibility, though. Understanding XHTML is a good way to get a firm grasp on how many web pages are created, and to enable you to read the source code of a large variety of sites.