You can define the content of a template using simple values, data expressions, or script expressions. Data Expression is a value read from a data source while a scripted expression is a value calculated through a Java Script. The script can use any number of variables and/or data source properties. Only Java Script is supported in the script expression box by Rational Publishing Engine. The scripted expression box allows you to write javaScript to calculate a value while the data expression box allows you to select only one property (or variable).