// In the case of an error, we suppress the error message.
function stopError() {
  return true;
}
window.onerror = stopError;

// Set variables that will eventually write our link tag.
var linkopen = '<link href="../css/';
var linkclose = '.css" rel="stylesheet" type="text/css" />';
var linkfile // This will be the name of the specific CSS file we determine is right for this browser.

// Get the browser name and basic version information, converted to all lower case to simplify testing.
var agt = navigator.userAgent.toLowerCase();
var appVer = navigator.appVersion.toLowerCase();

// Determine the browser version, and point release.
var is_minor = parseFloat(appVer);
var is_major = parseInt(is_minor);
// Internet Explorer always returns version 3 or 4 in the appVersion. We look further in the appVersion string for the actual version number.
var iePos = appVer.indexOf('msie');
if (iePos != -1) {
  is_minor = parseFloat(appVer.substring(iePos+5,appVer.indexOf(';',iePos)));
  is_major = parseInt(is_minor);
}
// Netscape 6 and Mozilla always return version 5 in the appVersion. We look further in the appVersion string for the actual version number.
var nav6Pos = agt.indexOf('netscape6');
if (nav6Pos !=-1) {
  is_minor = parseFloat(agt.substring(nav6Pos+10));
  is_major = parseInt(is_minor);
}

// The actual detection of the browser occurs here.
// is_nav is set to true if this is a Netscape or the Mozilla browser.
var is_nav = ((agt.indexOf('mozilla') != -1) && (agt.indexOf('spoofer') == -1) && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera') == -1) && (agt.indexOf('webtv') == -1));
// is_nav4 is set to true if this is Netscape 4.
var is_nav4 = (is_nav && (is_major == 4));
// is_nav6up is set to true if this is Netscape 6 or better (allows for future version 7+ releases) or the Mozilla browser.
// Testing is_minor for 5+ allows for the actual Mozilla browser to use the Netscape 6 CSS, since Mozilla reports itself as version 5.
// To exclude Mozilla, test is_minor for 6+.
var is_nav6up = (is_nav && is_minor >= 5);
// is_ie is set to true if this is the Internet Explorer browser.
var is_ie = (iePos != -1);
// ie_ie4up is set to true if this is Internet Explorer 4 or better (allows for future version 6+ releases).
var is_ie4up = (is_ie && is_minor >= 4);
// is_opera is set to true if this is the Opera browser.
var is_opera = (agt.indexOf('opera') != -1);

// Which (if any) CSS file we should write a link to is determined here.
if (is_nav) { // If this is Netscape or Mozilla....
  if (is_nav4) { // If this is Netscape 4....
    linkfile = 'nn4';
  }
  if (is_nav6up) { // If this is Netscape 6 or better, or Mozilla....
    linkfile = 'nn6';
  }
}
if (is_ie) { // If this is Internet Explorer....
  if (is_ie4up) { // If this is Internet Explorer 4 or better....
    linkfile = 'ie4';
  }
}
if (is_opera) { // If this is Opera....
  linkfile = 'op3';
}

// If an appropriate CSS file has been determined, write a link to it into the HTML
if (linkfile) {
  var linkhtml = linkopen + linkfile + linkclose;
  document.write(linkhtml);
}