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JavaScript Code Library
user_interface
BrowserDetector()
by Dr. Richard Blaylock

In order to deal with the many different browsers in use on the Web you need a way for your scripts to tell them apart. Luckily all browsers "announce" themselves with the User-Agent property, although it can be a pain to keep all the variations apart. The BrowserDetector function isolates the potentially useful portions of the User-Agent string so you can go about the business of making Web pages that work for all browsers.

Usage: var bd = new BrowserDetector(navigator.userAgent);

This will create a new BrowserDetector object named "bd" with the following properties (see the demo page for examples using actual User-Agent strings):

bd.browser

bd.platform

bd.version

bd.majorver

bd.minorver

Example: The following would redirect users to two different pages depending on whether they were using a version of Netscape or Internet Explorer.

  var bd = new BrowserDetector(navigator.userAgent);
  if (bd.browser == "Netscape") {
    location = "ns_version.html";
  }
  else if (bd.browser == "IE") {
    location = "ie_version.html";
  }

Demo (All JavaScript browsers )

Cut, paste, and enjoy!

/*
BrowserDetector()
Parses User-Agent string into useful info.

Source: Webmonkey Code Library
(http://www.hotwired.com/javascript/code_library/)

Author: Rich Blaylock
Author Email: blaylock@wired.com

Usage: var bd = new BrowserDetector(navigator.userAgent);
*/

// Utility function to trim spaces from both ends of a string
function Trim(inString) {
  var retVal = "";
  var start = 0;
  while ((start < inString.length) && (inString.charAt(start) == ' ')) {
    ++start;
  }
  var end = inString.length;
  while ((end > 0) && (inString.charAt(end - 1) == ' ')) {
    --end;
  }
  retVal = inString.substring(start, end);
  return retVal;
}

function BrowserDetector(ua) {

// Defaults
  this.browser = "Unknown";
  this.platform = "Unknown";
  this.version = "";
  this.majorver = "";
  this.minorver = "";

uaLen = ua.length;

// ##### Split into stuff before parens and stuff in parens
  var preparens = "";
  var parenthesized = "";

i = ua.indexOf("(");
  if (i >= 0) {
    preparens = Trim(ua.substring(0,i));
        parenthesized = ua.substring(i+1, uaLen);
        j = parenthesized.indexOf(")");
        if (j >= 0) {
          parenthesized = parenthesized.substring(0, j);
        }
  }
  else {
    preparens = ua;
  }

// ##### First assume browser and version are in preparens
// ##### override later if we find them in the parenthesized stuff
  var browVer = preparens;

var msieIndex = browVer.indexOf("MSIE");
  if (msieIndex >= 0) {
    browVer = browVer.substring(msieIndex, browVer.length);
  }

leftover = Trim(leftover);

// # Try to get version info out of leftover stuff
  i = leftover.indexOf(" ");
  if (i >= 0) {
    this.version = leftover.substring(0, i);
  }
  else
  {
    this.version = leftover;
  }
  j = this.version.indexOf(".");
  if (j >= 0) {
    this.majorver = this.version.substring(0,j);
    this.minorver = this.version.substring(j+1, this.version.length);
  }
  else {
    this.majorver = this.version;
  }

} // function BrowserCap

// -->

</script>

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