Whitespace
XML, unlike HTML, preserves whitespace in content.
In HTML, if you enter:
<h4>Bilbo Baggins</h4>
it will render as:
Bilbo Baggins
i.e., the extra whitespace is removed. (whitespace includes space, tab, and newlines).
XML will not remove whitespace from content in this way.
Comments
XML comments are almost like HTML comments:
<?xml version="1.0" encoding="utf-8"?>
<!-- Here follows an <address> tag
and it encloses <street>, <city>,
<state> and <zip> tags -->
<address>
<street>31 Concord Rd.</street>
<city>Lower Farthing</city>
<state>Old Hampshire</state>
<zip>99999</zip>
</address>
Click here to
see how this is rendered in your browser.
According to http://www.w3.org/TR/REC-xml/#sec-comments
:
Comments may appear anywhere in a document outside other
markup; in addition, they may appear within the document type
declaration at places allowed by the grammar. They are not part of the
document's character data; an XML processor MAY,
but need not, make it possible for an application to retrieve the text of
comments. For compatibility, the string "--"
(double-hyphen) MUST
NOT occur within comments.] Parameter entity references MUST
NOT be recognized within comments.
Here are some rules about where you can locate comments:
- Comments may not be placed before the XML declaration (Microsoft IE will
recognize them, but Firefox does not)
- Comments may not be placed inside a tag.
- Comments may be used to surround and hide tags
- The two hyphen (
--) string may not occur inside a comment,
except as part of its opening or closing tag. This also means that you
cannot use ---> (with the extra hyphen) to end a comment.
Note that XML comments are not part of the structure or semantics of an
XML document.
| 