As computers are becoming more interconnected it is desirable to make operating systems more customizable. XSL is a programming language that controls a software application. "Scripts" are considered different from "programs” that execute independently from other applications. At the same time they are also different from the core code of the application, which is usually written in a different language. Example: Perl, an extensible scripting language implemented in C.

Scripting languages are nearly always set in the application with which they are linked. The name "script" is derived from the written script used for performing arts, in which dialogue is set down to be spoken by human actors. In early days, script languages were called as batch languages or job control languages. They were created to shorten the traditional edit-compile-link-run process.

Character animations on most virtual environment systems are motions created off-line through motion capture techniques. These motions are then encoded and transmitted in a format called XML-based scripting language. XSL provides an “escape” into a scripting language to accommodate more sophisticated formatting tasks and to allow for extensibility and completeness. The scripting language can be used in XSL in a number of different ways. For example: At the top-level, variable declarations and function definitions may be specified within a define-script element.

Usage of Scripting Languages more than C:

Scripting languages are more preferred to be used rather than C for the following reasons:
# Scripting languages are higher-level computer languages, with more abstractions and hence they are useful for rapid prototyping.
# They are portable across many platforms. (Example: Java.)
# They possess a high degree of interactivity, fast turnaround, allows representation of programs as data.
# They have more runtime extensibility when compared with C programs. For example: New procedures and data types are defined in scripting language when the base program is still running. But in C it will require to recompile and restart the program to add a new data type to it.

Normally scripting languages are interpreted at the program text level and allows the user to type new programs while the program is still running. This is very useful when prototyping new programs, because it avoids the delay between typing in part and seeing it run. In C and other compiled languages the compilation time destroys this interactivity.

Apart from interactivity and extensibility, scripting languages have the advantage that the same program can run in more than one type of computer without modification. This is useful for portability and for exploring more dynamic types of programming.