function nuevoAjax()  {
        var xmlhttp=false;
        try
        {
                // Creacion del objeto AJAX para navegadores no IE
                xmlhttp=new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch(e)
        {
                try
                {
                        // Creacion del objet AJAX para IE
                        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
                }
                catch(E)
                {
                        if (!xmlhttp && typeof XMLHttpRequest!="undefined") xmlhttp=new XMLHttpRequest();
                }
        }
        return xmlhttp;
    }
	
	  function CambiaCat() {
              var cat=document.getElementById("lista_cat");
              var indice=cat.selectedIndex;
              var id=cat.options[indice].value;
              var http = false;
    
              if (id>0) {
                    var http = nuevoAjax();
                    http.open("GET", 'loadbibliorss.php?id='+id, true);
                    http.onreadystatechange=function() {
                    
                    
                       if(http.readyState == 4) {
                           var combo = document.getElementById('lista_rss');                         
                           combo.options.length = 0;                          
                           var response = http.responseText;
                           var items = response.split("%%%");
                           var count = items.length;
                           combo.options[0] = new Option('Seleccionar RSS','-1');
                           for (var i=1;i<count;i++){
                                  var options = items[i-1].split("&&");
                                  combo.options[i] = new Option(options[0],options[1]);
                           }                  
                        }

                  }
                    http.send(null);    
              } else {
                    var combo = document.getElementById('lista_rss');                         
                    combo.options.length = 1;
                    combo.options[0].text='Seleccionar RSS';
                    combo.options[0].value=-1;
              
              }  
    }         
  
     function ViewRSS() {
              var cat=document.getElementById("lista_cat");
              var indice=cat.selectedIndex;
              var id_cat=cat.options[indice].value;
              var rss=document.getElementById("lista_rss");
              var indice=rss.selectedIndex;
              var id=rss.options[indice].value;
              if (id>0) {
                  location.href="readrss.html?id_rss="+id+'&cat='+id_cat;
              }
     
     }