Server-side JavaScript is when the JavaScript source is executed in response to a request from a user's client application. That request arrives as a server, which then determines that a JavaScript needs to be executed to build the response. The server then runs the script and returns the output of it to the user, most likely in the form of a web page but possibly in the form of some image data or other textual or binary content.

Some server-side implementations are designed to yield performance improvements by semi-compiling the JavaScript and retaining that byte-code form in a cache.

Each server may offer alternative ways to invoke the server-side scripting. It is hoped that all the servers that use JavaScript and which conform to ECMAScript may well use the same tags for enclosing the server-side script. However, since the tags are not defined in the standard, this may be a vain hope.

Cross-references:

Wrox Instant JavaScript - page 3

Wrox Instant JavaScript - page 5

Wrox Instant JavaScript - page 64

Wrox Professional JavaScript - page 59-90