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12.1 Browser JavaScript Support

Dreamweaver's behaviors are implemented in JavaScript and therefore require a JavaScript-capable browser. Table 12-1 lists the JavaScript versions supported by the major browsers. (Microsoft's implementation of JavaScript is called JScript. Although JScript is very similar to JavaScript, it is not identical. If you create your own behaviors, test them in both Internet Explorer and Netscape.) Note that Dreamweaver's JavaScript debugger works with NN4.5+ (Macintosh and Windows) and IE4+ on Windows, but not earlier browsers, IE for Macintosh, NN6, or Opera.

Table 12-1. Scripting support in major browsers

Scripting language

Browser support

None

IE3 (Macintosh only) or any browser in which user has disabled JavaScript

JavaScript 1.0 (JScript 1.0)

IE3 (Windows only), NN2

JavaScript 1.1

NN3, Opera 3

JavaScript 1.2 (JScript 1.2)

IE4, NN4, Opera 4

JavaScript 1.3

IE5, IE5.5, NN4.0.7+, Opera 5

JavaScript 1.4

IE6, NN6

VBScript

IE3+ (Windows), IE5+ (Macintosh)

JavaScript support doesn't always correspond with a particular version, such as 1.2, 1.3, or 1.4. For example, some JavaScript 1.2 features were missing from Internet Explorer until IE5.5, and IE5.5 also supports some JavaScript 1.4 features. For a matrix of browser support for each JavaScript command see http://www.dwian.com/.

12.1.1 Browser Compatibility

You can safely assume that most visitors have a JavaScript-capable browser. If not, yours won't be the only site they have trouble accessing.

You should install the free Dreamweaver 4.01 update as it fixes some behaviors for use with NN6. Over 95 percent of web visitors use Version 4 or newer browsers. Supporting older browsers probably isn't worthwhile, except on your gateway (home) page to direct them to another page.

Macromedia has written robust behaviors, but not all work on all browsers and platforms. Whereas some behaviors work with 3.0 browsers, almost all work with 4.0+ browsers (see Table 12-3 for details). Use File figs/U2192.gif Check Target Browsers to find potential problems (mainly browsers that don't support particular events), but don't expect it to detect all incompatibilities. The File figs/U2192.gif Convert figs/U2192.gif 3.0 Browser Compatible command converts layers and CSS styles only. It does nothing to detect behavior incompatibility with 3.0 browsers nor does it modify a document's JavaScript code.

Ironically, the underpowered browsers you want to guard against are the same ones that don't allow accurate version checking or plugin checking. Furthermore, browser-to-plugin communication is not supported on IE for Macintosh (which is why you can't detect plugins or use the Dreamweaver debugger in that configuration). Conversely, automatic detection sometimes fails when new versions of plugins or browsers are released. (There is nothing so frustrating as being admonished to download a plugin that you have already installed.) Therefore, it is often better to let the user choose which version of a site to view rather than try to autodetect the browser's settings.

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