var xmlHttp;
var resulAJAX;
function llamadaAJAX(paraUrl, asincrono){

	resulAJAX = null;
	var URL = paraUrl;
	xmlHttp=GetXmlHttpObject(stateChanged);
	xmlHttp.open("GET", URL, asincrono);
	xmlHttp.send(null);
	return resulAJAX;
}

function llamadaAJAX_POST(paraUrl, parametros, asincrono){

	resulAJAX = null;
	var URL = paraUrl;
	xmlHttp=GetXmlHttpObject(stateChanged);
	xmlHttp.open("POST", URL, asincrono);
	xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	xmlHttp.send(parametros);
	return resulAJAX;
}

function stateChanged(){
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){
		//select_innerHTML(document.getElementById("tipdoc"),xmlHttp.responseText);
		//alert(xmlHttp.responseText);
		resulAJAX = xmlHttp.responseText;
	}
}

function GetXmlHttpObject(handler){
	var objXmlHttp=null;
	if (navigator.userAgent.indexOf("Opera")>=0){
		alert("Opera no soportado...")        
		return;    
	}
	if (navigator.userAgent.indexOf("MSIE")>=0){
		var strName="Msxml2.XMLHTTP"        
		if (navigator.appVersion.indexOf("MSIE 5.5")>=0)        
		{            
			strName="Microsoft.XMLHTTP"        
		}        
		try        
		{            
			objXmlHttp=new ActiveXObject(strName)            
			objXmlHttp.onreadystatechange=handler            
			return objXmlHttp        
		}        
		catch(e)        
		{            
			alert("Error. Scripting for ActiveX might be disabled")
			return        
		}    
	}
	if (navigator.userAgent.indexOf("Mozilla")>=0)    {        
		objXmlHttp=new XMLHttpRequest()        
		objXmlHttp.onload=handler        
		objXmlHttp.onerror=handler        
		return objXmlHttp   
	}
}