Scripting is a control mechanism which plays an important role in contemporary Web design. One of the simplest and most familiar uses of scripting is the rollover - when you move your mouse over something, something happens. This is usually used for links, or buttons, as in the example here.
Scripts can control images.
Here is an example of two ways of controlling a sequence of images. The buttons are self-explanatory. Click here to initiate one. This type of use for scripting can play an important role in making sure what you see is what your viewer gets.