Código:
// var b = new BrowserInfo();
// alert(b.version);
function BrowserInfo()
{
this.name = navigator.appName;
this.codename = navigator.appCodeName;
this.version = navigator.appVersion.substring(0,4);
this.platform = navigator.platform;
this.javaEnabled = navigator.javaEnabled();
this.screenWidth = screen.width;
this.screenHeight = screen.height;
}
Olvidaos de versiones anteriores al 4 de todos los navegadores, document.getElementById al poder!!!!!
Un saludo