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5.1 Detecting the Browser Brand
NN 2, IE 3
5.1.1 Problem
You want script execution to branch
one way for Netscape
Navigator users and another for Internet
Explorer users.
5.1.2 Solution
Use the
navigator.appName property to find out which brand the
browser purports to be. The following statement sets global Boolean
variables for browser brands:
var isNav = (navigator.appName = = "Netscape");
var isIE = (navigator.appName = = "Microsoft Internet Explorer");
5.1.3 Discussion
The navigator.appName property returns a string
that the browser maker determines. Netscape Navigator and Mozilla
always return the string
"Netscape", while Internet Explorer
returns "Microsoft Internet
Explorer". These strings and the equivalency
operator are case-sensitive.
You will also encounter some interesting aberrations to this scheme
once you roam from the IE and NN spheres. The Opera browser, for
example, reports that its appName is
"Microsoft Internet Explorer",
"Netscape", or
"Opera", depending on how the user
sets the preferences. Settings for IE and NN force the browser to
react to script syntax and objects along the lines of the selected
browser (at least for simple tasks). If you want to find out for sure
whether the browser is Opera,
you must dig into the navigator.userAgent
property, which contains more information about the browser. Here is
the default value for the navigator.userAgent
property from Opera 6:
Mozilla/4.0 (compatible; MSIE 5.0; Windows 98) Opera 6.03 [en]
The Opera-ness of this information is the string
"Opera" buried within that string.
Rather than look for the string at a particular location within the
string (which has changed over time), you can simply test whether
"Opera" is contained by
navigator.userAgent:
var isOpera = (navigator.userAgent.indexOf("Opera") != -1);With respect to Internet Explorer, you should be aware that
substantial differences exist between the Windows and Macintosh
versions. Thus, you may need operating-system detection as well
(covered in Recipe 5.5).
5.1.4 See Also
Recipe 5.2 through Recipe 5.4 for more granular browser version sniffing;
Recipe 5.5 for operating-system detection.
