In this section we shall briefly put names on the technologies we employ on the three tiers of the model. They are the name of the technologies you must master to be a web designer.
renders XHTML and CSS as web pages. The browser is also the platform. It is also the platform for client side dynamics, by being the interpreter of the programming language JavaScript, which is embedded in an XHTML document, a web page. Indirectly the browser also hosts the ActionScript programming language, which is embedded in a Flash-film. The browser utilizes a so called plugin, the Flash Player, to do this.
As a natural consequence JavaScript and ActionScript are called client side programming languages.
When the web page, the XHTML document, is static is is just transferred from the web server hard disk to the browser by the web server. Images, stylesheets, JavaScript files are automatically or may be shipped independently, but being part of the web page they are reassembled into the page by the browser.
Dynamic web pages. pages that are not the same each time they are viewed, are being processed into web pages by PHP or another so called server side programming language.
To manage the data forming the dynamic part of the dynamic web pages, we use a database server. The server program (system) is called an [R]DBMS, Relational Database Management System.
The communication between the PHP program and the concrete database is done through yet another programming language, SQL, Structured Query Language. SQL is a standardized language that is the same irrespective of chosen RDBMS.
SQL is a totally different kind of programming language, as we shall se in semester three. But it is labeled as a server side language anyway.
It is important to pay attention to the fact taht many RDBMS' have SQL as part of their names i.e. PostgreSQL, MySQL eller SQL Server. These are names of systems, NOT languages. They all are, as already said, operable through the common programming language SQL.