Something can be both XHTML and HTML5. They're compatible. But, yes, all websites written today should be compatible with both. Writing to the quirks in the HTML format just make people look incompetent (particularly as no quotes means certain characters cannot be used in the value, which is a nice bug waiting to happen).
So by all means keep writing your low quality quirky HTML and when it breaks in the future don't come crying to me. I prefer keeping my HTML both well formed and XML valid. The fact that writing strict HTMLs makes it much easier to automatically detect errors and typographic issues is just a huge bonus.
So by all means keep writing your low quality quirky HTML and when it breaks in the future don't come crying to me. I prefer keeping my HTML both well formed and XML valid. The fact that writing strict HTMLs makes it much easier to automatically detect errors and typographic issues is just a huge bonus.