This tutorial will teach you the basics of XML. The tutorial is divided into sections such as. XML Basics, Advanced XML, and XML tools. Each of these sections. We recommend reading this tutorial, in the sequence listed in the left menu. If you try all the examples, you will learn a lot about XML in a very short time!. Before you continue you should have a basic understanding of the following: •. HTML The following example is a note to Tove, from Jani, stored as XML.
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example, unlike HTML, every XML element must have both a start-tag and an There are three basic ways to tell a browser (specifically, Microsoft Internet Ex-. Basic XML Concepts. 3. Defining XML Data XML by Example. pdf">. A. This document is a basic tutorial on the practical use of XML with examples tailored The most basic building blocks of an XML file are elements, attributes and.
This information is not required to start this tutorial, but it will make the learning process easier. Advertise on Tizag. Applications of XML Although there are countless numbers of applications that use XML, here are a few examples of the current platforms and applications that are making use of this technology: Cell Phones - XML data is sent to some cell phones.
The data is then formatted by the specification of the cell phone software designer to display text or images, and even to play sounds! File Converters - Many applications have been written to convert existing documents into the XML standard.
Continue Download Tizag. Found Something Wrong in this Lesson? It includes information about which elements can be nested inside another, which elements are mandatory or optional, and what attributes can be included in an element. The resulting definition can be used to validate an XML document to make sure it conforms to the definition.
HTML documents are usually intended to be read by humans. The markup is primarily for semantic and presentational purposes, and is used by a web browser to render the document — but the final-user of HTML is almost always a person looking at a web page.
So, while validation of HTML is important and helpful, it is not strictly necessary. Browsers tend to be forgiving, and humans can figure out meaning even if the markup is a little off. But XML is used to transmit data, not web pages. XML is usually consumed by another piece of software, not a human. XML, on the other hand, is most often validated by the receiver.
This is done to ensure security and avoid errors before an application actually does something with the XML data. DTD vs. XSD can specify data types for each element; for example, whether an element should contain a date and time, a number, a string, or another type of data.
Since DTD is easier to create and read by humans, that is , it remained popular in contexts where XML was used for publishing information.
But, there are still plenty of DTDs in use. If you work on legacy web technology, especially data systems built in the late 90s, you will likely find yourself working with DTDs at some point. DTD Tutorial from W3Schools provides a methodical introduction to the topic, and is a good place to start if you are just coming to this topic.
Xmllint is a command-line tool for parsing and linting XML files. It can be used to quickly validate against a DTD. And XML itself has largely been replaced with newer technology. If you work with large enterprise systems, or develop using enterprise web tools like.
While E4X never enjoyed broad adoption and has been removed from all modern browsers, it is still used in some Flash other Adobe products. What is E4X?
E4X sounds pretty great, right? This actually predated the formal completion of the E4X specification, which was released more than two years later in Despite this early adoption, E4X implementation was uneven and inconsistent.
Entities can be phrases of text or special characters.
They can point internally or externally. Entities must be declared and expressed properly to avoid errors and to ensure proper display. You cannot typed special characters directly into your content. To use a symbol in your text, you must set it up as an entity using its character code.
You can set up phrases such as a company name as an entity, then type the entity throughout your content.
This code identifies the text that stands in for the entity. Using entities might help you avoid typing the same phrase or information repeatedly. It can also make it easier to adjust the text—perhaps if the company name changes—in many places with a simple adjustment in the entity definition.
If it displays your elements, attributes, and content, then the XML is well formed. If instead errors are displayed, you likely have a syntax error and need to review your document carefully for typos or missing tags and punctuation. As mentioned in Nest the elements , an element that contains another element is the parent of that contained element.
Remember to nest your sibling elements properly, as well. Listing 7 shows well-formed and properly nested XML. The line breaks make it easier for you to read your code and do not affect the XML.
You might wish to experiment with your test files, and move the end tags and beginning tags, to become familiar with the resulting error messages. In Figure 1 , your elements show up clearly when viewed within Internet Explorer.
Beginning and end tags surround your content. View image at full size.
Beyond a few simple rules, you have flexibility in designing your XML elements and attributes. Typing an XML document is also not difficult. What is difficult is figuring out what you need from your documents in terms of sortability or searchability, then designing elements and attributes to meet your needs. When you have a good idea of your goals and how to mark up your content, you can build efficient elements and attributes.
From that point, careful tagging is all you need to create well-formed and valid XML.
Sign in or register to add and subscribe to comments. United States. XML basics for new users An introduction to proper markup. Kay Whatley Published on February 24,