Now with node.js, it isn't as clear cut as you make out it to be. It's not there yet, but in the not so distant future, you can use node.js for your scripting needs.
Running on v8, it has an edge in terms of execution speed over other scripting languages. And the javascript syntax and semantics is something most of the developers are familiar with.
If you don't like writing nested closures, you have coffeescript which makes the code pretty, and also brings in some new features viz. list comprehensions, splats, satement modifiers etc.
I have written a certain amount of Javascript this year to run on Windows machines. This was because a) I needed the scripts to run on Windows, b) I did not wish to have to install another language (say Python) on the machines, c) I really really did not want to do them in VBScript.
Running on v8, it has an edge in terms of execution speed over other scripting languages. And the javascript syntax and semantics is something most of the developers are familiar with.
If you don't like writing nested closures, you have coffeescript which makes the code pretty, and also brings in some new features viz. list comprehensions, splats, satement modifiers etc.