XML Syntax (1)

The syntax of XML is very simple. The following are the sytax rules:

• A XML document must contain a pair, and only a pair, of root tags
• All XML elements must have a opening tag and a closing Tag.
• XML tags are case sensitive.
• An element in XML can has its child element.
• All elements in XML must be properly nested within each other.
• XML attribute values must be quoted.

As you may know that, HTML is quite forgiving when it comes to tag placement, missing tags, and attribute values. A web browser, for example, will correctly interpret an HTML page even if you forget to put a closing tag, like:

<p>Welcome to my website
<li>This is an element of a list

In XML, all elements must have a closing tag:

<firstname>Michael</firstname>
<lastname>Smith</lastname>

In HTML, tags are not case sensitive. you can use a tag like "<table>", or "<TABLE>", or "<Table>". They all are valid. But in XML, "<table>", or "<TABLE>", or "<Table>" will be three different tags because XML Tags are case sensitive. So you must write your opening and closing tags with the same case:

<Description>This is incorrect</description>
<description>This is correct</description>

In HTML, even the elements are improperly nested, it may still work.:

<b><i>This text is bold and italic</b></i>

XML Elements Must be Properly Nested:

<b><i>This text is bold and italic</i></b>

In the example above, "Properly nested" simply means that since the <i> element is opened inside the <b> element, it must be closed inside the <b> element.
XML Documents Must Have a Root Element.

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