So you don't need to install Java, and even if you would do so, it won't help:
I think this should state for most of the java script snipplets here on dostips.
Because of that the batch files execute such scripts using "cscript.exe" (or "wscipt.exe").
If i remember right, then the WSH should be preinstalled on any system since Windows XP.
If i'm wrong, then you have to install the .NET-Framework under Windows XP, but it is preinstalled since Windows Vista.
JScript is Microsoft's dialect of the ECMAScript.