Question

How can I put an & symbol in an attribute of an XML tag while keeping the XML valid?

<?xml version="1.0" ?> 
<a text="b&c"/>

When I use W3School’s validator, I get the error:

EntityRef: expecting ‘;‘

Answer 1

Use a character reference to represent it: &

See the specification:

The ampersand character (&) and the left angle bracket (<) MUST NOT appear in their literal form, except when used as markup delimiters, or within a comment, a processing instruction, or a CDATA section.

If they are needed elsewhere, they MUST be escaped using either numeric character references or the strings ”
&
” and ”
<
” respectively. The right angle bracket (>) may be represented using the string ”
>
“, and MUST, for compatibility, be escaped using either ”
>
” or a character reference when it appears in the string ”
]]>
” in content, when that string is not marking the end of a CDATA section.