var ns4 = ie4 = ie50 = ie55 = ns6 = dom = false;
var isIE = false;
var isNS = false;
if( document.layers ) ns4=true;
else if( document.all )
{
  if( parseFloat( navigator.appVersion.split( "MSIE " )[1].substr( 0, 3 ) ) <5 )
    ie4 = true;
  else if( parseFloat( navigator.appVersion.split( "MSIE ")[1].substr( 0, 3 ) ) == 5 )
    ie50 = true;
  else if( parseFloat( navigator.appVersion.split( "MSIE ")[1].substr( 0, 3 ) ) > 5 )
    ie55=true;
  isIE = true;
}
else if( navigator.appVersion.indexOf( "MSIE " ) == -1 )
{
  ns6 = true;
  isNS = true;
}

// El explorer 5.5 y netscape 6 y superiores aceptan dom
if( ie55 || ns6 )
  dom = true;

// Detectamos el os
var linux = false;
if( navigator.userAgent.toLowerCase().indexOf( 'linux' ) != -1 )
  linux = true;