function getInternetExplorerVersion()
// Returns the version of Internet Explorer or a -1
// (indicating the use of another browser).
{
  var rv = -1; // Return value assumes failure.
  if (navigator.appName == 'Microsoft Internet Explorer')
  {
    var ua = navigator.userAgent;
    var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
    if (re.exec(ua) != null)
      rv = parseFloat( RegExp.$1 );
  }
  return rv;
}
function checkVersion()
{
  var ver = getInternetExplorerVersion();

  if ( ver > -1 )
  {
    if ( ver >= 8.0 ) 
      document.write('<'+'link rel="stylesheet" type="text/css" href="style.css" />');
	else if ( ver == 7.0 )
	  document.write('<'+'link rel="stylesheet" type="text/css" href="style_ie7.css" />');
    else
      document.write('<'+'link rel="stylesheet" type="text/css" href="style_ie.css" />');
  }
}

var browser     = '';
var version     = '';
var entrance    = '';
var cond        = '';
// BROWSER?
if (browser == ''){
if (navigator.appName.indexOf('Microsoft') != -1)
browser = 'IE'
else if (navigator.appName.indexOf('Netscape') != -1)
browser = 'Netscape'
else browser = 'IE';
}
if (version == ''){
version= navigator.appVersion;
paren = version.indexOf('(');
whole_version = navigator.appVersion.substring(0,paren-1);
version         = parseInt(whole_version);
}
if (browser == 'IE' ) checkVersion();
if (browser == 'Netscape' ) document.write('<'+'link rel="stylesheet" type="text/css" href="style.css" />');