Attributes passed to custom components from Visualforce pages can be used wherever the merge syntax is legal. The <apex:outputText /> standard component can be used to format numeric and date values, but the formatting is limited to literal values rather than merge fields. In this scenario, an attribute indicating the number of decimal places to display for a numeric value cannot be used directly in the <apex:outputText /> component.
In this recipe we will create a custom component that accepts attributes for a numeric value and the number of decimal places to display for the value. The decimal places attribute determines which optional component is rendered to ensure that the correct number of decimal places is displayed, and the component will also bracket negative values. A Visualforce page will also be created to demonstrate how the component can be used.
