Most html 4 pages include a variety of common structures , such as headers , footers and columns and today , it is fairly common to mark them up using div elements , giving each a descriptive id or class .
Setting a height and a width are also vital here the height and width of this div should perfectly match the height and width of graphic elements 1 and 3 . And overflow : hidden ; hides the animated graphic , element 2 , when it extends outside the bounds of the wrapping div.
Thanks to the comments from the readers . Below is an example of the sky background using html selector to display the gradient background , so the # wrapper div tag is not required . It is a much more cleaner approach .