var objAjax={
            crear:function(url,proceso)
            {
                        http_request = false;
                        if (window.XMLHttpRequest) { // Mozilla, Safari,...
                                   var http_request = new XMLHttpRequest();
                                   if (http_request.overrideMimeType) { http_request.overrideMimeType('text/xml');}
                                   } else if (window.ActiveXObject) { // IE
                                   try {
                                               var http_request = new ActiveXObject("Msxml2.XMLHTTP");
                                   } catch (e) {
                                               try {
                                                           var http_request = new ActiveXObject("Microsoft.XMLHTTP");
                                               } catch (e) {}
                                   }
                        }
                        if (!http_request) {
                                   //alert('Giving up :( Cannot create an XMLHTTP instance');
                                   return false;
                        }
                        else
                        {  
                             http_request.onreadystatechange = function() {
		 	                 if (http_request.readyState == 4) 
			                  {
        		               if (http_request.status == 200) 
        		               {
    	                            eval(proceso+"(http_request.responseText)");
    	                       }
                		       else if (http_request.status == 204)
									alert('NO HAY RESPUESTA');
    	                      }
                          }
                        
	                   http_request.open("get", url,true);
    			       http_request.send(null);
                        
                       return http_request;
                        }
            }
}

var objAjaxConIndice={
            crear:function(url,proceso, indice)
            {
                 http_request = false;
                 if (window.XMLHttpRequest) { // Mozilla, Safari,...
	                   var http_request = new XMLHttpRequest();
                       if (http_request.overrideMimeType) { http_request.overrideMimeType('text/xml');}
                       } else if (window.ActiveXObject) { // IE
    	                    try {
                                var http_request = new ActiveXObject("Msxml2.XMLHTTP");
                            } catch (e) {
                                try {
                                   var http_request = new ActiveXObject("Microsoft.XMLHTTP");
                                } catch (e) {}
                            }
                        }
                        if (!http_request) {
                                   alert('Giving up :( Cannot create an XMLHTTP instance');
                                   return false;
                        }
                        else
                        {  
                             http_request.onreadystatechange = function() {
		 	                 if (http_request.readyState == 4) 
			                  {
        		               if (http_request.status == 200) 
        		               {
	        		              // alert(proceso+"(http_request.responseText, "+ indice+")");
                                   eval(proceso+"(http_request.responseText, "+ indice+")");
    	                       }
                		       else if (http_request.status == 204)
									alert('NO HAY RESPUESTA');
    	                      }
                          }
                          
	                      http_request.open("get", url,true);
    			          http_request.send(null);
                        
                          return http_request;
                       }
            }
}












/*






var isIE;
var completeTable;
var completeField;
var autorow;
 

function init() {

    completeTable = document.getElementById("tb_ruta");
    completeTable.setAttribute("bordercolor", "white");
}

   function calcularRuta() {
   	   var  req;
    if (window.XMLHttpRequest) {
        isIE=false;
        req = new XMLHttpRequest(); 
    } else if (window.ActiveXObject) {
        isIE = true;
        req = new ActiveXObject("Microsoft.XMLHTTP");
    }
//           alert('HAS ENTERADO');
		selectDestino = document.getElementById("origen");
		selectOrigen= document.getElementById("destino");
		
		TxtOrigen = selectOrigen.options[selectOrigen.selectedIndex].text;
		TxtDestino = selectDestino.options[selectDestino.selectedIndex].text;

          var url = "ServRuta?accion=ruta&origen="+TxtOrigen+"&destino="+TxtDestino;
  //       var  req = initRequest(url);
           req.onreadystatechange = function() {
         //   alert('SI HAY RESPUESTA 0');
                   if (req.readyState == 4) {
                       if (req.status == 200) {
                       //   alert('SI HAY RESPUESTA 1');
                           parseMessages(req.responseXML);
                       } else if (req.status == 204){
                            alert('NO HAY RESPUESTA');
                            clearTable();
                       }
                   }
           }
           req.open("get", url,true);
           req.send(null);

   }

  function parseMessages(responseXML) {

   alert('SI HAY RESPUESTA');

       clearTable();
           var employees = responseXML.getElementsByTagName(
                   "nodos")[0];
       if (employees.childNodes.length > 0) {
           completeTable.setAttribute("bordercolor", "black");
           completeTable.setAttribute("border", "1");
       } else {
           clearTable();
       }
    
       for (loop = 0; loop < employees.childNodes.length; loop++) {
           var employee = employees.childNodes[loop];
           var texto = employee.getElementsByTagName(
                   "texto")[0];
           var tiempo = employee.getElementsByTagName(
                   "tiempo")[0];

           var nodoId = employee.getElementsByTagName(
                   "id")[0];
           appendEmployee(
                   texto.childNodes[0].nodeValue, 
                   tiempo.childNodes[0].nodeValue,
                   nodoId.childNodes[0].nodeValue);
       }
   }
function clearTable() {

    if (completeTable) {
      completeTable.setAttribute("bordercolor", "white");
      completeTable.setAttribute("border", "0");
      completeTable.style.visible = false;
      for (loop = completeTable.childNodes.length -1; loop >= 0 ; loop--) {
        completeTable.removeChild(completeTable.childNodes[loop]);
      }
    }
}
   
   
function appendEmployee(texto,tiempo,nodoId) {

    var textoCell;
    var tiempoCell;
    var row;
    var nameCell;
    if (isIE) {
        row = completeTable.insertRow(completeTable.rows.length);
        
        nameCell = row.insertCell(0);
         tiempoCell =row.insertCell(1);
    } else {
        row = document.createElement("tr");
        nameCell = document.createElement("td");
        tiempoCell = document.createElement("td");
        row.appendChild(nameCell);
        row.appendChild(tiempoCell);
        completeTable.appendChild(row);
    }
    row.className = "popupRow";
    nameCell.setAttribute("bgcolor", "#FFFAFA");

    

    
    nameCell.appendChild(document.createTextNode(texto));

    tiempoCell.appendChild(document.createTextNode(tiempo));
    
}*/