Why are dashes preferred for CSS selectors / HTML attributes?

Question

In the past I\'ve always used underscores for defining class and id attributes in HTML. Over the last few years I changed over to dashes, mostly to align m

Answer 1

I think it's a programmer dependent thing. Someones like to use dashes, others use underscores.
I personally use underscores (_) because I use it in other places too. Such as:
- JavaScript variables (var my_name);
- My controller actions (public function view_detail)
Another reason that I use underscores, is this that in most IDEs two words separated by underscores are considered as 1 word. (and are possible to select with double_click).