var browser = navigator.appName;
var b_version = navigator.appVersion;
var version = parseFloat( b_version );
var is_explorer7 = false;
var is_explorer8 = false;
var position = b_version.indexOf( "MSIE 7." );
var position = b_version.indexOf( "MSIE 8." );
if( position != -1 )
{
is_explorer7 = true;
}

if ( browser == "Microsoft Internet Explorer" )
{
if ( version >= 5.5 || is_explorer7 )
{
// alert("Your browser is good enough!" + version );
}
else
{
location = 'oldbrowser.html';
}
}