JavaScript has an impressive list of capabilities. Note, however,
that they are confined to browser-related and HTML-related tasks.
Since JavaScript is used in a limited context, it does not have
features that would be required for standalone
languages:
- JavaScript does not have any graphics
capabilities, except for the ability to format and display
HTML (which, however, does include images, tables, frames,
forms, fonts, and other user-interface elements).
- For security reasons, client-side JavaScript does not
allow the reading or writing of files. Obviously, you
wouldn't want to allow an untrusted program from any random
web site to run on your computer and rearrange your files!
- JavaScript does not support networking of any
kind, except--an important exception!--that it can
cause a web browser to download the contents of arbitrary
URLs.
- Finally, JavaScript doesn't have any
multithreading capabilities, except whatever comes
implicitly from the web browser's internal use of threads.
