Scripting languages in general are fully-fledged programming languages administered by php developers. Constantly improved thanks to the constant evolution of microprocessors and peripherals, it becomes just as comfortable to program in an interpreted language, as in a compiled language. The main advantage is the ease of maintaining or upgrading a program written in script. A script makes it easier to add a function to a menu, to automate tasks with routines to adapt them to new needs. But the essential feature of a scripting language is its portability on other operating systems.
Server-side interpreted scripts
In fact, scripts can be written in languages such as PHP, ASP or Python: this is interpreted as Server side script. Concretely, if you observe the source code of a web page with a tool like Firebug, you will not see this code. It is read by the server (the machine where the site is hosted), interpreted by him, then sent to the client (your terminal: computer, tablet, smartphone ...) in the form of html code.
Scripts interpreted on the client side
Consequences for users
Many CMS are programmed in PHP. Coupled with a database (often MySQL), they allow to display pages from templates, in which they insert content. We are talking about dynamic websites.
To conclude, it can be seen that there are a large number of interpreted languages available on the Net for people of different levels. The development of many interpreted languages essentially comes from the fact that it is much easier to create an interpreter rather than a compiler.