For example, see Column 18, JavaScript Animations, Part I and Column 19, JavaScript Animations, Part II . Using dynamic properties, you would write much less code. You still need to specify in the beginning of your code the functional dependency of element properties, and then you let JavaScript do the job for you. You don't have to touch these elements ever again. Dynamic properties do not avoid JavaScript scripting at all, but with a little coding, you make a lot of coding obsolete.
Dynamic properties are similar to a spreadsheet's implementation of a formula.
A cell's value can be a constant or a formula. A formula can include references to any number of other cells in the spreadsheet. Likewise, a dynamic property can reference properties of other elements on the same document, as well as regular variables and functions. One of the benefits of dynamic properties is that once you find the functional dependency, you don't have to monitor or maintain the page. You describe in formulas the mathematical dependency between objects, properties, and variables.