Build Your Own Website:
Part 2: JavaScript

Who: Our Vice President, Yoni Teitz
Where: Belfer Hall Room 430
When: Wednesday, March 8th, 2011. 8:30 PM

The second presentation on Web Design and Development will cover the practical uses of JavaScript. The primary use of JavaScript is to write functions that are embedded in or included from HTML pages and that interact with the Document Object Model (DOM) of the page. Some simple examples of this usage are:

  • Opening or popping up a new window with programmatic control over the size, position, and attributes of the new window (e.g. whether the menus, toolbars, etc. are visible).
  • Validating input values of a web form to make sure that they are acceptable before being submitted to the server.
  • Changing images as the mouse cursor moves over them: This effect is often used to draw the user's attention to important links displayed as graphical elements.

Because JavaScript code can run locally in a user's browser (rather than on a remote server), the browser can respond to user actions quickly, making an application more responsive. Furthermore, JavaScript code can detect user actions which HTML alone cannot, such as individual keystrokes. Applications such as Gmail take advantage of this: much of the user-interface logic is written in JavaScript, and JavaScript dispatches requests for information (such as the content of an e-mail message) to the server. The wider trend of Ajax programming similarly exploits this strength.

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