You can define the content of a template using simple values, data expressions, or script expressions. A data expression is a value read from a data source while a scripted expression is a value calculated through a JavaScript. The script can use any number or combination of variables and data source properties. Only JavaScript 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 one variable.