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RIA & Ajax: Article

Real-World AJAX Book Preview: Some Basic JavaScript Tools

Real-World AJAX Book Preview: Some Basic JavaScript Tools

This content is reprinted from Real-World AJAX: Secrets of the Masters published by SYS-CON Books. To order the entire book now along with companion DVDs for the special pre-order price, click here for more information. Aimed at everyone from enterprise developers to self-taught scripters, Real-World AJAX: Secrets of the Masters is the perfect book for anyone who wants to start developing AJAX applications.

Some Basic JavaScript Tools
Learning JavaScript can be a pain, largely because in most cases you're either limited to working in the browser's command line or building JavaScript in script blocks and leaning heavily on the refresh button in a browser.

While JavaScript command-line environments are available, one of the more useful is an extension to the Firefox browser. Ted Mielczarek's Extension Developer extension (http://ted.mielczarek.org/code/mozilla/extensiondev/) is actually a wonderful tool to experiment on many aspects of Mozilla's XUL and JavaScript features, but it includes a live JavaScript environment as part of its package that you can test scripts in.

If you have Firefox (and if you're developing AJAX applications you probably should have Firefox), then go to the site listed above and select the Install link. This will, in all likelihood, bring up a window at the top of the page indicating that you have to specify this site as being one that you can download programmatic content from. Click the button in the dialog to change the settings, then add the site to the ones you've permission to download from. Then click on the link to the extension and this will open the extension dialog and add it into the environment. Finally, you'll have to restart Firefox.

Once restarted, you'll have a number of buttons on the toolbar along with a new menu item in the Tools menu (see Figure 2.1). Pressing either the JS button or the JavaScript Shell entry will launch the JavaScript Shell (see Figure 2.2), an area where you can enter commands or create objects and have them persist in memory. This is an incredibly useful development tool, since it lets you prototype JavaScript objects before trying to run them as scripts and lets you play with the capabilities of the language.

Keep in mind that the version of JavaScript exposed by this interface is that used by Mozilla's C++ Seamonkey JavaScript language (version 1.5 or 1.6 depending on the version of Firefox you're using). Internet Explorer uses an earlier version of the language (which will be covered later in this chapter), so once you develop an object in JavaScript under this interface you should be very scrupulous in testing it in IE.

This content is reprinted from Real-World AJAX: Secrets of the Masters published by SYS-CON Books. To order the entire book now along with companion DVDs, click here to order.

More Stories By Kurt Cagle

Kurt Cagle is a developer and author, with nearly 20 books to his name and several dozen articles. He writes about Web technologies, open source, Java, and .NET programming issues. He has also worked with Microsoft and others to develop white papers on these technologies. He is the owner of Cagle Communications and a co-author of Real-World AJAX: Secrets of the Masters (SYS-CON books, 2006).

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