Navigator 2.0, Internet Explorer 3.0
navigator.userAgent
navigator.userAgent is a read-only string property that specifies the value the browser uses for the user-agent header in HTTP requests. In Navigator 2.0 and 3.0, this property is the value of navigator.appCodeName followed by a slash and the value of navigator.appVersion. For example:
Mozilla/2.01 (Win16; I)
In Internet Explorer 3.0, this property has the value "Mozilla/2.0 (compatible; MSIE 3.0A; Windows 95)". Once again, this is the value of appCodeName followed by a slash and the value of appVersion.