XML Declaration
Definition
When XHTML is served as XML, it is good practice to use an XML declaration that identifies the version of XML being used.
Example
This is an example of an XML declaration:
<?xml version="1.0" encoding="UTF-8"?>
The XML declaration should appear before the DOCTYPE as shown below:
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>XHTML Reference</title></head><body>...</body></html>