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 msg = "You're not using Internet Explorer.";
  var ver = getInternetExplorerVersion();
  if ( ver > -1 )
  {
    if ( ver < 8.0 )
	{
      msg = "You're using an old or outdated version of Internet Explorer, as a result this page may not display correctly. You can upgrade for free by visiting windowsupdate.microsoft.com in your web browser. Alternatively there is nothing preventing you from proceeding, however you may not fully enjoy this website as the designer intended";
	  alert( msg );
	 }
  }
  
}