mozilla

Revision 129553 of Una re-introduzione a Javascript

  • Slug della versione: Una_re-introduzione_a_Javascript
  • Titolo della versione: Una re-introduzione a Javascript
  • ID versione: 129553
  • Data di creazione
  • Autore: Kyuzz
  • Versione corrente? No
  • Commento

Contenuto della versione

Introduzione

Perché una re-introduzione? Perché è ragionevole ritenere che JavaScript sia il linguaggio di programmazione meno compreso del mondo. Spesso deriso come un giocattolo, dietro la sua ingannevole semplicità si celano alcune caratteristiche molto potenti. Il 2005 ha visto il lancio di un certo numero di applicazioni JavaScript di alto profilo, mostrando che una più profonda conoscenza di questa tecnologia è requisito importante per ogni sviluppatore web.

It's useful to start with an idea of the language's history. JavaScript was created in 1995 by Brendan Eich, an engineer at Netscape, and first released with Netscape 2 early in 1996. It was originally going to be called LiveScript, but was renamed in an ill-fated marketing decision to try to capitalise on the popularity of Sun Microsystem's Java language — despite the two having very little in common. This has been a source of confusion ever since.

Microsoft released a mostly-compatible version of the language called JScript with IE 3 several months later. Netscape submitted the language to Ecma International, a European standards organisation, which resulted in the first edition of the ECMAScript standard in 1997. The standard received a significant update as ECMAScript edition 3 in 1999, and has stayed pretty much stable ever since, although edition 4 is currently in the works.

This stability is great news for developers, as it's given the various implementations plenty of time to catch up. I'm going to focus almost exclusively on the edition 3 dialect. For familiarity, I will stick with the term JavaScript throughout.

Unlike most programming languages, the JavaScript language has no concept of input or output. It is designed to run as a scripting language in a host environment, and it is up to the host environment to provide mechanisms for communicating with the outside world. The most common host environment is the browser, but JavaScript interpreters can also be found in Adobe Acrobat, Photoshop, Yahoo!'s Widget engine, and more.

Sorgente della versione

<p>
</p>
<h3 name="Introduzione"> Introduzione </h3>
<p>Perché una re-introduzione? Perché è ragionevole ritenere che <a href="it/JavaScript">JavaScript</a> sia il <a class="external" href="http://javascript.crockford.com/javascript.html">linguaggio di programmazione meno compreso del mondo</a>. Spesso deriso come un giocattolo, dietro la sua ingannevole semplicità si celano alcune caratteristiche molto potenti. Il 2005 ha visto il lancio di un certo numero di applicazioni JavaScript di alto profilo, mostrando che una più profonda conoscenza di questa tecnologia è requisito importante per ogni sviluppatore web.
</p><p>It's useful to start with an idea of the language's history. JavaScript was created in 1995 by Brendan Eich, an engineer at Netscape, and first released with Netscape 2 early in 1996. It was originally going to be called LiveScript, but was renamed in an ill-fated marketing decision to try to capitalise on the popularity of Sun Microsystem's Java language — despite the two having very little in common. This has been a source of confusion ever since.
</p><p>Microsoft released a mostly-compatible version of the language called JScript with IE 3 several months later. Netscape submitted the language to <a class="external" href="http://www.ecma-international.org/">Ecma International</a>, a European standards organisation, which resulted in the first edition of the <a href="it/ECMAScript">ECMAScript</a> standard in 1997. The standard received a significant update as <a class="external" href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">ECMAScript edition 3</a> in 1999, and has stayed pretty much stable ever since, although edition 4 is currently in the works.
</p><p>This stability is great news for developers, as it's given the various implementations plenty of time to catch up. I'm going to focus almost exclusively on the edition 3 dialect. For familiarity, I will stick with the term JavaScript throughout.
</p><p>Unlike most programming languages, the JavaScript language has no concept of input or output. It is designed to run as a scripting language in a host environment, and it is up to the host environment to provide mechanisms for communicating with the outside world. The most common host environment is the browser, but JavaScript interpreters can also be found in Adobe Acrobat, Photoshop, Yahoo!'s Widget engine, and more.
</p>
Ripristina questa versione