Every so often I run into someone who has drunk the XHTML koolaid. For a long time I didn't really know what to say to them about it; while I have strong opinions about this, my usual discussion of this is fairly long and somewhat tedious, and thus not quite the thing to drop into conversation to convince people. What I needed was not a long reasoned argument against XHTML (complete with a careful inventory of its practical problems) and in favour of, say, HTML 4.01, but a 30 second elevator pitch.

Recently I finally came up with one (although I haven't actually put it to the test yet):

HTML 4.01 Strict is just as well defined and parseable as XHTML, and it is much more likely to be interpreted predictably and as you intend by user agents.

Since this is an elevator pitch, it's not intended to be the entire argument; if the XHTML-using person was actually interested in the issues, I would expect to have to expand on basically all of this.

It's possible that this is not a convincing elevator pitch because it doesn't really address the reasons that most people use XHTML. My cynical side thinks that most XHTML use is basically cargo cult HTML, so maybe the right elevator pitch would be some sort of snappy statement about how XHTML is not actually standards compliant in practical usage, or how all the cool people are now using HTML 5.

(Although I believe that most browsers now interpret mis-served XHTML pages in 'standards mode' not 'random tag soup HTML' mode, I don't think that any browser actually interprets them as XHTML.)

As a side note, I suspect that part of my elevator pitch here is incorrect, in that most people likely intend their XHTML to be interpreted by user agents just as it is being now and would be horrified if it was interpreted as actual XHTML.