Which XHTML DTD is suitable for DotNetNuke®?
Transitional is the suitable format for DotNetNuke. This is because at present, DotNetNuke does not produce valid XHTML code. You may create a skin to XHTML strict standards, but there are no guarantees what standards the modules that DNN uses have been produced to. Therefore the transitional DOC TYPE allows us to set a browser to use standard compliance mode while still allowing for modules and core DNN code to use deprecated code.