[docbook-apps] HTML customizations

[Sanjaya Liyanage]

Hi dev,
      I am going through the book "DocBook XSL: The Complete Guide - 4th
Edition" and in chapter 12 book addresses  class.value mode and the
class.attribute mode.I got the facts regarding the class.value mode but have
the below doubts regarding the latter.

   1.     How can we indicate the customisation layer about the class.value?
   2.     What is the relationship between the class.value and
   class.attribute mode?

 Any clarification will be a great help for me.

Thank you.
Sanjaya Liyanage.