One of the coolest things with XHTML is that it is an XML language, so you can apply any kind of XML tools to it.
One of the terrible thing with XHTML (and XML more generally) is how hard it is sometimes to get it right.
One of the depressing thing with building tools based on XML for Web technologies is that most of the content out there is in HTML (or the tag soup that some people call with that name), or in ill-formed XHTML.
For quite some time, Mozilla’s bug about not recognizing the application/*+xml MIME Type as an XML Mime Type has made my life harder than it should be; that’s especially true for RDF files served as application/rdf+xml (see the proposed registration of this MIME Type). Enough being enough, I’ve set up a work around this bug in my Gnome 2.6 + Galeon 1.3 set up; it’s not clear how much of this can be re-used in other environments, although I think it’s likely it should work with other Gnome+Mozilla derivatives set up.
When developing a CGI script and before putting on the production server, you need to test it; to catch runtime errors, but more generally, to check if you get the expected result depending on the parameters.
To emulate a GET request without setting up a Web server, the easiest method is probably to set the QUERY_STRING and REQUEST_METHOD environment variables and run the script through its interpreter, e.g. REQUEST_METHOD="GET" QUERY_STRING="foo=bar" php4 filename.php.
Well, this used to work till recently – I assumed it broke with PHP 4.3 release; nowadays, the php4 executable comes in two flavours: the CLI and the CGI SAPI; the former is designed to be use out of Web context, so isn’t much relevant to this case.