I am developing a simple webpage at hostgator.com. I have the standard headers, but when I add the following line:
<?xml version="1.0" encoding="utf-8"?>
the page does not work. I would like why.
This is the full header:
<?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" lang="es" xml:lang="es">
... rest of code ...
The server returns me a blank page
Issue solved: The PHP short tags was open.
My best guess is that:
- The document is being processed as PHP
- Short Tags are turned on
… so the server is trying to process the XML declaration as PHP code. Normally I'd expect an error message, but perhaps there is a PHP setting in play that suppresses errors to the client to avoid leaking data that could be potentially useful to someone trying a security exploit.
Just remove it.
- UTF-8 is the default
- version 1.0 is the default
- It is optional in the spec
- Given a text/html content-type, an XML prolog will trigger IE6's quirks mode
The latter is undesirable. The former all mean it makes no difference.
来源：https://stackoverflow.com/questions/4361750/why-when-add-xml-version-1-0-encoding-utf-8-to-web-page-don%c2%b4t-work-on-ho