Only VBScript 5.0 offers runtime code evaluation. This version comes with Windows 2000, Windows 98 Second Edition (Win98SE), and Microsoft Internet Explorer (IE) 5.0. If you aren't using any of these products, you can obtain VBScript 5.0 through Windows Script Host (WSH) 2.0 or as a separate download from the Microsoft Developer Network (MSDN) Web site at http://msdn.microsoft.com/scripting.
The addition of runtime code evaluation makes VBScript superior to its parent language Visual Basic for Applications (VBA) because VBA doesn't offer runtime code evaluation. This addition also makes VBScript more of an equal to its sister language, JScript. Although only the most recent version of VBScript offers runtime code evaluation, JScript has had this feature since its inception. As of version 5.0 of both languages, the runtime code evaluation functionality is similar, with these exceptions:
- JScript doesn't offer a feature equivalent to VBScript's ExecuteGlobal statement.
- Although JScript's eval( ) function returns values just as VBScript's Eval function does, JScript's eval( ) works more like VBScript's Execute statement. JScript's eval( ) always modifies the local scope.
- In JScript, no ambiguity is possible with the = operator because JScript uses different operators for assignment (=) and comparison (= =).