XML Elements
An XML document contains XML Elements.
What is an XML Element?
An XML element is everything from (including) the element's start tag to (including) the element's end tag.
An element can contain other elements, simple text or a mixture of both. Elements can also have attributes.
<bookstore>
<book category="CHILDREN">
<title>Harry Potter</title>
<author>J K. Rowling</author>
<year>2005</year>
<price>29.99</price>
</book>
<book category="WEB">
<title>Learning XML</title>
<author>Erik T. Ray</author>
<year>2003</year>
<price>39.95</price>
</book>
</bookstore> |
In the example above, <bookstore> and <book> have element contents, because
they contain other elements. <author> has text content because it contains text.
In the example above only <book> has an attribute (category="CHILDREN").
XML Naming Rules
XML elements must follow these naming rules:
- Names can contain letters, numbers, and other characters
- Names cannot start with a number or punctuation character
- Names cannot start with the letters xml (or XML, or Xml, etc)
- Names cannot contain spaces
Any name can be used, no words are reserved.
Best Naming Practices
Make names descriptive. Names with an underscore separator are nice: <first_name>, <last_name>.
Names should be short and simple, like this: <book_title> not like this: <the_title_of_the_book>.
Avoid "-" characters. If you name something "first-name," some software may think you want to subtract name from first.
Avoid "." characters. If you name something "first.name," some software may think that "name" is a property of the object "first."
Avoid ":" characters. Colons are reserved to be used for something called namespaces (more later).
XML documents often have a corresponding database. A good practice is to use the naming rules of your database for the elements in the XML documents.
Non-English letters like יעב are perfectly legal in XML, but watch out for problems if your software vendor doesn't support them.
XML Elements are Extensible
XML elements can be extended to carry more information.
Look at the following XML example:
<note>
<to>Tove</to>
<from>Jani</from>
<body>Don't forget me this weekend!</body>
</note> |
Let's imagine that we created an application that extracted the <to>, <from>, and <body> elements from the XML document to produce this output:
|
MESSAGE
To: Tove
From: Jani
Don't forget me this weekend!
|
Imagine that the author of the XML document added some extra information to it:
<note>
<date>2008-01-10</date>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note> |
Should the application break or crash?
No. The application should still be able to find the <to>, <from>, and <body> elements in the XML document and produce the same output.
One of the beauties of XML, is that it can often be extended without breaking applications.
Make your web applications look like a million bucks
|
|
Most web applications today use boring methods to present data to their viewers using grids or simple HTML tables. FusionCharts induces "life" into the web applications by converting monotonous data into lively charts, gauges & maps.
FusionCharts works with all technologies like ASP, ASP.NET, PHP, ColdFusion, Ruby on Rails, JSP, HTML pages etc.
and connects to any database to render animated & interactive charts. It takes less than 15 minutes and no expertise
whatsoever to build your first chart and just a glance of it to captivate your audience. This fact is endorsed by our
12,000 customers and 150,000 users which include a majority of the Fortune 500 companies.
And yeah, your applications could look like a million bucks by spending just $69.
So go ahead, download your
copy of FusionCharts and start "wow-ing" your customers now!
|
 |
W3Schools' Online Certification Program
The perfect solution for professionals who need to balance work, family, and career building.
More than 4000 certificates already issued!
|
The HTML Certificate documents your knowledge of HTML, XHTML, and CSS.
The JavaScript Certificate documents your knowledge of JavaScript and HTML DOM.
The XML Certificate documents your knowledge of XML, XML DOM and XSLT.
The ASP Certificate documents your knowledge of ASP, SQL, and ADO.
The PHP Certificate documents your knowledge of PHP and SQL (MySQL).
| 
