In the class selector we don't need to write <div> tag M I right ??

Question

class selector

Answer 1

You're right. In css you may use tag selector eg. span {} class selector .classname {} or id sector #elemenid {}

you may also "combine": span.classname {} applys to <span class="classname"> but not <div class="classname">

chaining: div span .classname {}
every classname that are within div and span elements

and so on.

Answer 2

That was just a quick one: see more about css selectors here http://www.w3schools.com/cssref/css_selectors.asp