Introduction to Server Side JavaScript

In the preceding tutorials, we've concentrated on using JavaScript on web pages - Client Side JavaScript. There is also another application of JavaScript, with its own commands, capabilities and syntax - Server-Side JavaScript. Netscape has released a set of commands that are used on its Enterprise Web Server, called Netscape's Server Side Additions. The use of Server Side JavaScript is mostly limited to maintaining user sessions and handling user requests and form submissions. Cookies are huge with Server Side JavaScript.

While Netscape was releasing its own line of Web Servers, Microsoft was developing something of its own, called Active Server Pages. These Active Server Pages perform much the same as server side JavaScript on the Netscape Enterprise servers, but differ enough to require a separate set of tutorials. Microsoft's Active Server Pages (ASP) won't be discussed here, only Server Side JavaScript implemented the Netscape way.

Server Side versus Client Side

When working with client side JavaScript, everything was scripted. That is, it wasn't run through a compiler before it was able to be executed. The browser just reads it and acts upon your instructions. Server side JavaScript differs from client side in that it must be compiled into a byte- code file, usually with a .web extension. That is pretty much the major difference you'll find in the actual process of deploying your script. The commands differ of course, but this is the big difference.

Within an HTML page, your script was contained within the opening and closing HTML SCRIPT tags. Leaving out these tags resulted in the browser rendering your script as just more textual content to be displayed in the browser window. With server side JavaScript, the SCRIPT tags are replaced with opening and closing SERVER tags (<SERVER> and </SERVER>). You can see that there is no huge difference here.

Some of the major difference you'll find in dealing with server side JavaScript is the ability to send mail, access and write to multiple database's, access and manage user driven data requests, and the specific handling of user provided data. You'll be the king of your domain!! (pun intended).

You'll also notice that you'll have to mesh your client side scripting with your server side scripting - some client side commands won't work on the server side. An upcoming Server Side JavaScript Tutorial will address these issues and discuss every available command in depth, with examples.

Compiling Your Server Side Script

• -a version - This switch allows you to specify the version of the JavaScript Interpreter to use when compiling your server side script. Currently the only option is for JavaScript version 1.2 - "javascript1.2" (exactly, no quotes, no spaces).
• -c - This switch is used to verify the script you are about to compile. Any errors thrown by the script will be reported. A compiled .web file is not generated when this switch is used. Also, do not use this switch with the -o switch.
• -d - This switch is used to display the JavaScript script contained within all of the files which are to be compiled into a .web file. Very useful to verify that you've included the proper files to be compiled.
• -f filelist - This switch is used to give JSAC a list (.txt file only, please) of all of the files to include in the compiled .web file. The file names should be separated with a space. Any file names that have a space in them should be stated within quotes to avoid any confusion on the part of the JSAC Application.
• -h - This switch will display the help files associated with JSAC. This switch should be used on its own, with no other switches.
• -i input file - This switch is used to give the name of a single .html file to be used for the compilation into a .web file. Note that you should use the -f switch to specify multiple files.
• -0 output file - This switch is used to specify the name of the file that is to be compiled. It is the compiled file name of .web extension. Do not use this switch with the -c switch.
• -p path - This switch is used to specify the root directory from which all of the relative filenames you provide will be referenced from. It is similar in functionality to the HTML BASE tag.
• -r error file - This switch is used to specify the filename and location of a file which will contain all of the errors (if any) which occurred during the compilation of your server side script into a .web file.
• -v - This switch will display a "verbose" description of all of the operations which occurred during the compilation of your script into a .web file.

You may use these switches together in combinations, with the exception of the -c and -o switches. You can see that the creators of the Enterprise Web Server have included a lot of switches to make your use of their product easier and less of a headache. If the switches don't quite make sense, take a look at the following command line instructions given to the JSAC Application.

jsac -o sscompiled.web -v fileOne.html fileTwo.html external.js -r errors.log 

The above commands tell JSAC to compile the files fileOne.html fileTwo.html external.js into the .web file sscompiled.web. Notice the -v switch has been used to tell you what has been happening, switching on the verbose feature. The -r switch was used to turn on the function that writes any errors to the file you specify, in this case the errors.log file. Simple.

Pattern Matching - The RegExp Object - Continued
The JavaScript Chronicles
Database Connectivity via Server Side

The JavaScript Chronicles