Browser Detection

• All browsers expose a UA (User Agent) string
• Write scripts based on the browser

  Browser		App Version
  IE 4.01 (Win 95)		4.0 (compatible; MSIE 4.01; Windows 95);
  Navigator 4.04 (Win 95)		4.04 [en] (Win95; I; Nav)

• Getting the Version: ""

    // Pulls the integer from the beginning of the string
    var version = parseInt(navigator.appVersion) 

• Is it IE?

    var isIE = navigator.appVersion.indexOf("MSIE")>0
    var isNav = navigator.appVersion.indexOf("Nav")>0
    var isIE4 = isIE && version>=4
    var isNav4 = isNav && version>=4

• Authoring Browser specific code