var xmlHttp
   
   function MandaID(str)
   { 
   xmlHttp=GetXmlHttpObject()
   if (xmlHttp==null)
   {
   alert ("Este browser não suporta HTTP Request")
   return
   }
   var url="js/seleciona_modelo.asp"
   url=url+"?id_marca="+str
   xmlHttp.onreadystatechange=stateChanged 
   xmlHttp.open("POST",url,true)
   xmlHttp.send(null)
   }
   
   function stateChanged() 
   { 
   if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
   { 
	   document.getElementById("exibe_modelo").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
   }