Sometimes referred to as SSI, is a simpler interpreted server-side scripting language used almost exclusively for the world-wide-web.
SSI is most frequently used to include the contents of one or more web-pages on a web-server.
SSI’s are useful for including a common piece of code throughout an entire sight, such as a page header, footer, or navigation menu.
For example, if a web-page wished to contain a daily quotation it could be included by placing the following code into the file of the webpage:
With a single change of the quote.txt file, all the pages containing the file will display the most recent quotation.
Includes can also be utilized for text output from a program or other actions such as the value of a system variable, like the current time.
Files needing to be recognized by an SSI-enabled HTML file have to end with a special extension, such as .shtml, .stm, and .shtm.
SSI supports only one data type, text, and its control flow is fairly simple. Because the design of SSI is so simple it is easier to learn and use over many server-side scripting languages.