Batch and JSCript hybrids

Introduction#

JScript is actually the superset of Javascript (it’s 1.8.1 version - so some newer features are not available ), and they can be embedded into a batch script for extending batch script’s functions. Usually, techniques of embedding are using the JScript directives (not part of the official Javascript standard) in order to separate the batch and JScript code. JScript allows you to work with Com/ActiveX objects, as well as with WMI objects in addition to the standard Javascript.

Embedded JScript In a Batch File

This following example is created by user Michael Dillon from this answer.

Consider the following script:

@set @junk=1 /*
@echo off
cscript //nologo //E:jscript %0 %*
goto :eof
*/

//JScript aka Javascript here

This script snippet does:

Execute the cscript command which calls itself with all the arguments provided.
As the part after @set @junk=1 is commented(/* and */ Are valid JScript comment),
JScript will ignore them.
Note: We need the @set @junk=1 part because the batch file does not recognize /* as a command, but a set statement will be a workaround. JScript will recognize /* as a comment so the other batch file will not be executed by JScript engine.

You can add your JScript after */ and start extending your batch file scripting!

Run JScript With Temporary Files

As mentioned here, the old-school method to run another script is by using temporary files. Simple echo it into a file and then run it(and remove it optionally).

Here’s the basic concept:

@echo off
echo //A JS Comment > TempJS.js
echo //Add your code>>TempJS.js

cscript //nologo //e:cscript.exe TempJS.js

del /f /s /q TempJS.js

But this would require lots of echo statements to create a relatively large JScript. Here’s a better method by Aacini.

@echo off
setlocal

rem Get the number of the "<resource>" line
for /F "delims=:" %%a in ('findstr /N "<resource>" "%~F0"') do set "start=%%a"

rem Skip such number of lines and show the rest of this file
(for /F "usebackq skip=%start% delims=" %%a in ("%~F0") do echo %%a) > TempJS.js

cscript //nologo //e:cscript.txt TempJS.js
del /f /s /q TempJS.js

goto :EOF

<resource>
JScript
JScript
JScript