var xmlHttp

function mostraModelos(str)
{ 

xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
{
alert ("Browser does not support HTTP Request")
return
} 

var url="shared/modelos.asp"
url=url+"?marca_id="+str
url=url+"&sid="+Math.random()
xmlHttp.onreadystatechange=stateChanged 
xmlHttp.open("POST",url,true)
xmlHttp.send(null)

}

function stateChanged() 

{ 


if(xmlHttp.readyState == 1) { // Quando estiver carregando, exibe uma camada: Carregando...

var conteudo=document.getElementById("carrega")
conteudo.style.visibility = "visible";

}

if(xmlHttp.readyState == 4||xmlHttp.readyState=="Complete")
{ 
var conteudo2=document.getElementById("carrega")
conteudo2.style.visibility = "hidden";
document.getElementById("txtHint").innerHTML=xmlHttp.responseText 
} 
} 

function GetXmlHttpObject()
{ 
var objXMLHttp=null
if (window.XMLHttpRequest)
{
objXMLHttp=new XMLHttpRequest()
}
else if (window.ActiveXObject)
{
objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")
}
return objXMLHttp
}