The Explorer6 CSS max-width property.

        .fixed {
            max-height: 200px;
            _height: expression(this.scrollHeight > 200 ? 200 + 'px' : 'auto');
        }

Dynamic properties simplify and minimize the amount of code required in a document. Authors can use dynamic properties to implement functionality formerly possible only with scripting. This frees authors from the requirement of learning script programming before they can design advanced features for their pages. Dynamic properties are similar to a spreadsheet's implementation of a formula. In a spreadsheet, 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 other properties on the same document. Dynamic properties enable Web authors to describe relationships between objects, properties, and variables in terms of functions, rather than specify an explicit sequence of steps to follow. Authors merely need to concentrate on functions without constantly monitoring the current state of the document. Handling events can get fairly involved and inefficient. Implementing event handlers on a document that is not fully known at design time (database driven Web pages or pages with data binding, for example) is only possible with event bubbling. As a result, authors frequently implement a single global handler at the top of the event chain to update everything. On the other hand, with dynamic properties, authors can automatically determine a minimal and optimal recalculation of properties and evaluate only the expressions that really need to be evaluated.