Tuto WEBDEV 25

30 Part 1: Discovering WEBDEV Principle of Browser/Server How does it work? An Internet or intranet site operates as follows: • The client (the Web user) is using a browser to access the site. • The browser sends a request to the server that is hosting the requested site. In this request, it indicates the page that must be displayed and different parameters allowing the server to build the corresponding page. • The server receives this request, processes it and returns the corresponding "HTML" page. HTML (HyperText Markup Language) is the language used by all browsers to display the Web pages. Therefore, there are two types of events: • Events run at browser level, on the Web user’s computer. • Events run at server level. The code run at browser level is called JavaScript code. The browsers can only run JavaScript code. And in WEBDEV? With WEBDEV, everything is developed: • in WYSIWYG ("What You See Is What You Get") in the editor: your pages are visually identical in creation and at run time. • in WLanguage for the programming side. WEBDEV converts your page created in the editor into HTML page that can be read by the browsers. The server code is run in WLanguage. The browser code is converted into JavaScript. To create a site with WEBDEV, a single language is required: WLanguage. However, two types of code are available: server code and browser code. Why this distinction between server/browser? For performance reasons. Indeed, between the browser and the server stands Internet, with its response time, latency, ... Some simple operations can be performed on the browser directly, without having to go back to the server.