JScript is a language that continues to evolve and each new version of the language introduces new features. To take advantage of all the features provided by a particular version of the language, a compatible version of compiler or script engine is required.
When writing code for a server-side application or a command-line program, the version of the compiler and the versions of JScript that it supports are usually known. However, when writing client-side scripts that run in the script engine of a browser, the running script detects the engine version. Once the engine version is known, a script written in a compatible version of JScript can be run. For more information, see Detecting Browser Capabilities.
The following table lists the version of Microsoft JScript implemented by host applications.
|Microsoft Internet Explorer 3.0||x|
|Microsoft Internet Information Server 3.0||x|
|Microsoft Internet Explorer 4.0||x|
|Microsoft Internet Information Server 4.0||x|
|Microsoft Internet Explorer 5.0||x|
|Microsoft Internet Explorer 5.01||x|
|Microsoft Windows 2000||x|
|Microsoft Internet Explorer 5.5||x|
|Microsoft Windows Millennium Edition||x|
|Microsoft Internet Explorer 6.0||x|
|Microsoft Windows XP||x|
|Microsoft Windows Server 2003||x|
|Microsoft .NET Framework 1.0||x|
Note The version number reported by the ScriptEngineMajorVersion function and the @_jscript_version conditional compilation variable is always numeric. This allows numeric comparisons to be made with the version number. For version .NET applications, the version reported is 7.x, not .NET. This means that engines that report a version number of 7.x or higher can compile JScript .NET code.
The following table lists JScript language features and the version when first introduced.