Question

Yes, I’ve googled it, and surprisingly got confusing answers.

One page says that < > & " are the only reserved characters in (X)HTML. No doubt, this makes sense.

This page says < > & " ' are the reserved characters in (X)HTML. A little confusing, but okay, this makes sense too.

And then comes this page which says < > & " © ° £ and non-breaking space (&nbsp) are all reserved characters in (X)HTML. This makes no sense at all, and pretty much adds to my confusion.

Can someone knowledgeable, who actually do know this stuff, clarify which the reserved characters in (X)HTML actually are?

EDIT: Also, should all the reserved characters in code be escaped when wrapped in <pre> tag? or is it just these three — < > & ??

Answer 1

Only < and & need to be escaped. Inside attributes, " or ' (depending on which quote style you use for the attribute’s value) needs to be escaped, too.

<a href="#" onclick="here you can use ' safely"></a>
<a href="#" onclick='here you can use " safely'></a>