Web browsers read documents written in HTML, and then interpret them into the visual representation the designer intends. However, we are seeing the emergence of Extensible Markup Language (XML) in web design, in conjunction with HTML, to enhance a web site’s features, search-ability, and unlike HTML, it was designed not to display data, but to carry data.
So what do you need to know about each? To begin with, when designing a webpage, you will likely be using HTML to structure and outline it. HTML displays data by way of certain elements known as “tags.” A tag might look like this
signifying the end of the element, with the data to be displayed placed in between the two. A browser will not display the tags, but will instead display the data contained within the tags according to the specifications outlined by the tags.
Elements can also have attributes, which are conditions that change the appearance of the data. For example, an HTML tag that looks like this: Italic
! will be displayed like this in a web browser: Italic tag! HTML can be used to design webpages that have tables, various colors, images and links and a wide variety of backgrounds and enhancements.
XML is also a markup language, but unlike HTML, it is not used to design a webpage, but to help carry data around and from the webpage. XML tags are now being used by web designers to aid in the webpage’s ability to be found on a search by using tags to alert the search engine that the webpage has the information being sought by the searcher. XML by itself does not actually do anything, so why use it?
To begin with, XML allows you to “invent” your own tags, as opposed to being forced to HTML’s existing, predefined tag structure and use. This is especially helpful if you are trying to display data that does not already have a predefined tag in HTML. An XML element, for example, might look like this in a webpage code:
. XML allows the designer to designate the element “date” as a tag, something not originally allowed in HTML.
XML is most often used for webpages designed to transmit certain data, such as RSS and databases. Remember, XML enhances HTML, it does not replace it. However, if you are learning web design, with the emerging dynamic web, learning XML along with HTML will become a necessity to keep your webpage competitive int he evolving web.