XML syntax
There are a few more restrictions
on XML than on HTML; they make parsing of XML simpler.
Tags cannot be omitted
Unlike HTML, XML does not allow you to omit tags. This guarantees
that parsers know where elements end.
The following example is acceptable HTML, but not XML:
|
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<table><br>  <tr><br>    <td>Dog</td><br>    <td>Cat<br>    <td>Mouse<br></table> |
To change this into well-formed XML, you need to add all the
missing end tags:
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1 |
<table><br>  <tr><br>    <td>Dog</td><br>    <td>Cat</td><br>    <td>Mouse</td><br>  </tr><br></table> |
Representing empty elements
Empty elements cannot be represented in XML in the same way
they are in HTML. An empty element is one that is not used to mark
up data, so in HTML, there is no end tag. There are two ways to
handle empty elements:
-
Place a dummy tag immediately
after the start tag. For example:1<img href="picture.jpg"></img> -
Use a slash character at the end of the initial
tag:1<img href="picture.jpg"/>This tells a parser that the element consists only of one
tag.
XML is case sensitive
XML is case sensitive, which allows it to be used with non-Latin
alphabets. You must ensure that letter case matches in start and
end tags: <MyTag> and </Mytag> belong
to two different elements.
White space
White space within tags in XML is unchanged by parsers.
All elements must be nested
All XML elements must be properly nested. All child elements
must be closed before their parent elements close.