One of the terms that newcomers to web design or web hosting may fail to understand is the word script, or scripts. What is meant by this term? In simple terms, a script is a segment of computer code that can extend or alter the way that the web browser interprets the HTML code that makes up a web page. The result of this type of alteration is known as Dynamic HTML, or DHTML. Such scripts can be split in to two different classes; client-side scripts, which are executed by the users’ own web browser software, or server-side scripts, where the HTML to be sent to the browser is altered by a script running on the web server itself. Let’s take a closer look at each type.

As I said above, client-side scripts are executed by the users’ own web browser. These scripts can be used for a number of different things. Some depend on input from the user, for example to change an image when the user moves the mouse pointer over it, while others need no user input – an example of this would be a script that displays the current time and date as part of the web page. The majority of these client-side scripts are written in JavaScript, though other languages such as Visual Basic Script, or VBScript, are sometimes used.

Client-side scripts can be used in one of two ways. Many are written as part of the HTML code for the web page – this is known as an embedded script. Others are written as a separate file, which is accessed as needed from the web server. This is still client-side scripting though, as the actual execution of the script takes place on the users’ own web browser.

The use of client-side scripting has both advantages and disadvantages. The script does not need to use the resources of the web server; however the script does require that the users’ web browser can interpret it properly. Although less of a problem nowadays, there may still be occasions when a particular browser does not display the results of the script in the way that the writer intended.

In contrast to this, a server-side script is a script that is run on the web server itself, and the resulting web page is then delivered to the user, normally in the form of HTML code. One common use for such server-side scripts are to act as interfaces to databases, for example for use as a shopping cart for an ecommerce site, although there are many other uses. Server-side scripts are normally written in PHP or Perl, for Unix/Linux based web servers, or ASP, which is normally used on Windows-based servers.

As with client-side scripting, server-side scripting also has both advantages and disadvantages. The HTML code that is produced by a server-side script is not dependant on the browser used to view the code, meaning that output should, at least theoretically, be identical across all browsers. However, in order to use server-side scripts, the interpreter for the language used to write the script must be installed on the web server. If you are looking for a hosting service for your web site, then make sure that any support you need for server-side scripting is available.