var sBrowser; 
var sVersion; 
var aBrowFull = new Array("opera", "msie", "netscape", "gecko", "mozilla"); 
var aBrowVers = new Array("opera", "msie", "netscape", "rv",    "mozilla"); 
var aBrowAbrv = new Array("op",    "ie",   "ns",       "mo",    "ns"   ); 
var sInfo = navigator.userAgent.toLowerCase(); 

 
sBrowser = ""; 
for (var i = 0; i < aBrowFull.length; i++)
	    { 
     		if ((sBrowser == "") && (sInfo.indexOf(aBrowFull[i]) != -1))
		    { 
      			sBrowser = aBrowAbrv[i]; 
      			sVersion = String(parseFloat(sInfo.substr(sInfo.indexOf(aBrowVers[i]) + aBrowVers[i].length + 1)));
     		} 
    	} 
if((sBrowser=='ie')&&(sVersion=='6'))
{
    document.write('<header><link rel="stylesheet" href="css/estilo_ie6.css" mce_href="ie.css" type="text/css" /></header>');
}
else
{
    document.write('<header><link rel="stylesheet" href="css/estilo_fx.css" mce_href="ie.css" type="text/css" /></header>');
}