WebReference.com - Part 3 of Chapter 6 from Designing with JavaScript (4/4)

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Designing with JavaScript, 2nd Edition

Beyond the browser

JavaScript is not limited to detecting just browsers and plug-ins; it can also determine the operating system on which a browser is running. As we saw back in Table 6-2, the navigator.appVersion property includes information about the operating system as well. Table 6-3 shows appVersion values for some common operating systems (the browser version information has been taken out, because it is irrelevant to our purpose here).

With this knowledge, you can create simple functions to determine which operating system a visitor is using. Example 6-12 shows a function that uses indexOf() to determine if a browser is running on Windows 98.

function isWin98() {
    if (navigator.appVersion.indexOf("98") != -1) {
        return true;
    }
    else {
        return false;
    }
}

Example 6-12: Is the platform Windows 98?

You can use this function, which returns true if the browser is running on Windows 98, to tailor parts of your page, just as you did with the browser detection script. For example:

if (isWin98()) {
    document.write("You're running Windows 98");
}

Pesky details
Navigator and IE report Windows 98 as "Win98" and "Windows 98", respectively. Searching for "98" bridges the gap.

If the platform is Windows 98, the script prints "You're running Windows 98".

Think of it this way: if it's in the appVersion, you can detect it. This ability opens up many doors. For example, say your company develops software for a number of different operating systems. When visitors come to your site to download software, you can save them the trouble of specifying their operating system by doing it for them with JavaScript.

You can also easily combine operating system detection and browser detection, or operating system detection and plug-in detection. They're all interchangeable. Never again will your visitors have to make decisions based on their software (and hardware); you can do it for them.

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Created: December 27, 2001
Revised: December 27, 2001

URL: http://webreference.com/programming/javascript/designing/chap6/3/4.html