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DOM:window.navigator.userAgent

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« Gecko DOM Reference

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[edit] Summary

Returns the user agent string for the current browser.

[edit] Syntax 

var ua = window.navigator.userAgent;

[edit] Value

ua stores the user agent string value of the current browser.

The window.navigator.userAgent property is read-write; it has no default value.

The user agent string is built on a formal structure which can be decomposed into several pieces of info. Each of these pieces of info comes from other navigator properties which are also settable by the user. Gecko-based browsers comply with the following general structure: 

userAgent = appCodeName/appVersion number (Platform; Security; OS-or-CPU; 
Localization; rv: revision-version-number) product/productSub 
Application-Name Application-Name-version

[edit] Example 

alert(window.navigator.userAgent)
// alerts "Mozilla/5.0 (Windows; U; Win98; en-US; rv:0.9.2) Gecko/20010725 Netscape6/6.1"

[edit] Notes

Browser identification based on detecting the user agent string is unreliable and is not recommended, as the user agent string is user configurable. For example:

  • Mozilla Suite and Firefox can use the preference "general.useragent.override" in about:config. Some Firefox extensions or multi-bar do that.
  • Opera 6+ allows users to set the browser identification string via a menu
  • Microsoft Internet Explorer uses the Windows registry
  • Safari and iCab allow users to change the browser user agent string to predefined Internet Explorer or Netscape strings via a menu.

[edit] Specification

DOM Level 0. Not part of any standard.

[edit] References

Retrieved from "http://developer.mozilla.org/en/docs/DOM:window.navigator.userAgent"