var xmlHttp;
var campoDestino;
function callAjax(catalogo,campo_destino,parametros){
    xmlHttp=GetXmlHttpObject()
    if (xmlHttp==null){
        alert ("El Browser no soporta HTTP Request")
        return
    }
    var url="/ProcessAjax";
    var variables= "catalog_name="+catalogo+"&campo_destino="+campo_destino+"&"+parametros;
    campoDestino = campo_destino;
    xmlHttp.onreadystatechange=stateChanged;
    xmlHttp.open("POST",url,true);
    xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    xmlHttp.send(variables);
}


function stateChanged(){    
    if (xmlHttp.readyState == 4) {//completado
            if (xmlHttp.status == 200) {//exitosamente
                eval("document.getElementById('"+campoDestino+"').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
}