class attribute

In HTML class attribute helps to add a certain class or name to an element and therefore allows to create a CSS rule for a specific element. Therefore class attribute provides wider customization options for an element and makes website design vivid and element specific. Class attributes are used in both CSS and JavaScript. In HTML5 class attribute can be applied to all the elements. Class attribute can start with any Latin letter or digit.

There are no restrictions as for the class names but, of course, it’s in your interest to make class relevant to the content. In case you plan to set different style for the same elements, make sure to specify unique class name of each element in a group.