JavaScript è un linguaggio di scripting orientato agli oggetti e multi piattaforma. Questa guida ti spiegherà tutto quello che devi sapere sull'uso di javascript.
New features in JavaScript versions
- /it/docs/JavaScript/New_in_JavaScript/1.2
- /it/docs/JavaScript/New_in_JavaScript/1.3
- /it/docs/JavaScript/New_in_JavaScript/1.4
- /it/docs/JavaScript/New_in_JavaScript/1.5
- /it/docs/JavaScript/New_in_JavaScript/1.6
- /it/docs/JavaScript/New_in_JavaScript/1.7
- /it/docs/JavaScript/New_in_JavaScript/1.8
- /it/docs/JavaScript/New_in_JavaScript/1.8.1
- /it/docs/JavaScript/New_in_JavaScript/1.8.5
Cosa dovresti già sapere
This guide assumes you have the following basic background:
- Conoscenzegenerali su Internet e il World Wide Web (WWW).
- Buone conoscenze operative dell' HyperText Markup Language (HTML).
- Qualche esperienza di programmazione. Se sono le prime volte che sviluppi, prova qualche tutorial dalla pagina JavaScript (en).
Diverse versioni di javascript
| JavaScript version | Navigator version |
|---|---|
| JavaScript 1.0 | Navigator 2.0 |
| JavaScript 1.1 | Navigator 3.0 |
| JavaScript 1.2 | Navigator 4.0-4.05 |
| JavaScript 1.3 | Navigator 4.06-4.7x |
| JavaScript 1.4 | |
| JavaScript 1.5 | Navigator 6.0 Mozilla (open source browser) |
| JavaScript 1.6 | Firefox 1.5, other Mozilla 1.8-based products |
| JavaScript 1.7 | Firefox 2, other Mozilla 1.8.1-based products |
| JavaScript 1.8 | Firefox 3, other Gecko 1.9-based products |
Dove Trovare Informazioni su JavaScript
JavaScript documentation includes the following books:
- JavaScript Guide (this guide) provides information about JavaScript language and its objects.
- JavaScript Reference provides reference material for JavaScript language.
If you are new to JavaScript, start with the JavaScript Guide. Once you have a firm grasp of the fundamentals, you can use the JavaScript Reference to get more details on individual objects and statements.
Tips for learning JavaScript
Getting started with JavaScript is easy: all you need is a modern Web browser. This guide includes some JavaScript features which are only currently available in the latest versions of Firefox (and other Gecko powered browsers), so using the most recent version of Firefox is recommended.
An interactive interpreter
An interactive JavaScript prompt is an invaluable aid to learning the language, as it enables you to try things out interactively without having to save a file and refresh a page. The Firefox Error Console (Tools-Web Developer-Web Console) provides a simple way to try interactive JavaScript: Just enter a line of code and click the "Evaluate" button.
Firebug
A more advanced interactive prompt is available using Firebug, a Firefox extension. Expressions you type are interpreted as objects and linked to other parts of Firebug. See some examples below:
Using the arrow on the right bottom corner gives a command editor for multiline scripts.
Firebug also provides an advanced DOM inspector, a JavaScript debugger, a profiling tool and various other utilities. JavaScript code running in a Web page can call, console.log(), a function that prints its arguments to the Firebug console.
Document conventions
JavaScript applications run on many operating systems; the information in this book applies to all versions. File and directory paths are given in Windows format (with backslashes separating directory names). For Unix versions, the directory paths are the same, except that you use slashes instead of backslashes to separate directories.
This guide uses uniform resource locators (URLs) of the following form:
http://server.domain/path/file.html
In these URLs, server represents the name of the server on which you run your application, such as research1 or www; domain represents your Internet domain name, such as netscape.com or uiuc.edu; path represents the directory structure on the server; and file.html represents an individual file name. In general, items in italics in URLs are placeholders and items in normal monospace font are literals. If your server has Secure Sockets Layer (SSL) enabled, you would use https instead of http in the URL.
This guide uses the following font conventions:
The monospace fontis used for sample code and code listings, API and language elements (such as method names and property names), file names, path names, directory names, HTML tags, and any text that must be typed on the screen. (Monospace italic fontis used for placeholders embedded in code.)- Italic type is used for book titles, emphasis, variables and placeholders, and words used in the literal sense.
- Boldface type is used for glossary terms.