Cards with revolving interest on a daily or monthly?

When it comes to revolving credit cards there ‘a lot of confusion as regards the calculation of interest, in fact this can be daily or monthly, depending on the cards. There ‘someone who panic when they read that this can be on a daily basis!
Actually it would be preferable that was always so, as in this case the interest is calculated only from the day that is an expense. For example, if buying an online article on 25 of the month, interest will I be computed from 25 and the first of the month … which happens when the calculation is on a monthly basis.