function GetXMLHttp() {  
	if (navigator.appName == "Microsoft Internet Explorer") {  
		xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");  
	} else {  
		xmlHttp = new XMLHttpRequest();  
	}  
	return xmlHttp;  
}  
var mod = GetXMLHttp();  
  
function carregaModelos(valor) {  
	mod.open("GET", "modelos_combo_busca.asp?id_marca="+valor, true);  
	mod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");  
	mod.onreadystatechange = function() {  
		if (mod.readyState == 4) {  
			document.getElementById("lista_modelos_busca").innerHTML = mod.responseText;  
		}  
	};  
	mod.send(null);  
}