If you came to XML, RSS, or Atom from an HTML background then you have probably already found that many of the entities you used in HTML don't work.

Although XML, by default, defines the following 5 entities:

XML Entity	Description	Symbol
&	Ampersand	&
&lt;	Less Than Sign	<
&gt;	Greater Than Sign	>
&quot;	Double Quote	"
&apos;	Apostrophe	'

Many of the entities you are probably familiar with do not by default exist in XML. Entities like ©, ·, and many others; including  .

Probably the most frustrating to me at times is the lack of support for  . Especially when embedding XHTML into an Atom <atom:content type="xhtml"> element.

Here's how to make   work in XML, RSS, and Atom.

What is a  

The   entity is the HTML entity for a non-breaking space. A non-breaking space is a special space character that prevents a line break when a line wrapping algorithm is applied to render the text.

In HTML one of the common uses for the   is to get multiple consecutive spaces in a row.

XML Entities and Unicode Code Points

In Unicode, each and every character has a numerical value. Here's some examples:

Character	Description	Decimal Value	Hexadecimal Value
E	Capital "E"	69	45
x	Lowercase "x"	120	78
	Non-Breaking Space	160	A0
‽	Interrobang	8253	203D
♥	Heart	9829	2665

In XML, you can use any Unicode characters with a special type of entity. (Although your browser may or may not have a font glyph to render the character on screen.)

You can either use the Unicode numerical decimal value of a character. As in ‽ for Interrobang.

Or you can use the Unicode numerical hexadecimal value of a character. As in ‽ for Interrobang.

Although the decimal form of these types of entities is better supported in the common web browsers. (So, for the Interrobang, it would be better to use ‽ rather than ‽.)

The Other Non-Breaking Space Entity

So to use   in XML, RSS, and Atom, it's simple. Use the following entity:

 

It's that simple.

-- Charles Iliya Krempeaux, B.Sc.