if (document.layers) {
        //alert("NetScape");
        n=1;ie=0;ff=0
      }
      if (document.all) {
        //alert("InternetExplorer");
        n=0;ie=1,ff=0
      }
      if (document.getElementById&&!document.all){
        //alert("fireFox");
        n=0;ie=0;ff=1
      }

      function init(elem_a_mostrar) {
              scrollActive = 0;
              scrollLimit = -750; //scroll del censo
              if (elem_a_mostrar=='')
                scrollContentShown = "elem1"
              else
                scrollContentShown = elem_a_mostrar;
      }

      function scroll(direction) {
        if (scrollActive) {
          if (n){
            var top = eval("document.principal.document.elementos.document." + scrollContentShown + ".top");
            //alert("top="+top);
          }
          if (ie){
            var top = eval(scrollContentShown + ".style.pixelTop");
            //alert("top="+top);
          }
          if (ff){
            //alert(scrollContentShown);
            var top = eval("document.getElementById('"+scrollContentShown+"').style.top");
            if (top==''){
              //alert("top=VACIO:"+top);
              document.getElementById(scrollContentShown).style.top=0;
            }else{
              //alert("top=NO-VACIO:"+top);
            }
            top=eval("document.getElementById('"+scrollContentShown+"').style.top");
            //alert("direccion:"+direction+"_top="+top);
            top=parseInt(top);
            //alert("direccion:"+direction+"_top="+top);
          }
          if (direction == "up" && top < 0) {             // ver si ya esta arriba del todo
            var inc = 10    // mover de 10 en 10 px
            //alert("En UP");
            if (n)
              eval("document.principal.document.elementos.document." + scrollContentShown + ".top += inc")
            if (ie)
              eval(scrollContentShown + ".style.pixelTop += inc")
            if(ff)
              document.getElementById(scrollContentShown).style.top=parseInt(document.getElementById(scrollContentShown).style.top)+inc;

            setTimeout("scroll('up')",20)
          }
          if (direction == "down" && top > scrollLimit) {  // ver si ya esta abajo del todo
            //alert("En DOWN");
            var inc = -10   // mueve de 10 en 10 px
            if (n)
              eval("document.principal.document.elementos.document." + scrollContentShown + ".top += inc")
            if (ie)
              eval(scrollContentShown + ".style.pixelTop += inc")
            if(ff)
              document.getElementById(scrollContentShown).style.top=parseInt(document.getElementById(scrollContentShown).style.top)+inc;

              setTimeout("scroll('down')",20)
          }
          if (direction == "inicio" && top < 0) {          // mover al principio del todo
            if (n)
              eval("document.principal.document.elementos.document." + scrollContentShown + ".top = 0")
            if (ie)
              eval(scrollContentShown + ".style.pixelTop = 0")
            if(ff)
              document.getElementById(scrollContentShown).style.top=0;

            setTimeout("scroll('inicio')",20)
          }
        }
      }

      //que elemento / el maximo de px a dexplazarlo
      function scrollChange(which,limit) {
          if (n) {
             eval("document.principal.document.elementos.document." + scrollContentShown + ".visibility = 'hide'")
             eval("document.principal.document.elementos.document." + which + ".visibility = 'show'")
          }
          if (ie) {
             eval(scrollContentShown + ".style.visibility = 'hidden'")
             eval(which + ".style.visibility = 'visible'")
          }
          if(ff){
            //alert("cambio de scroll");
            eval("document.getElementById('"+scrollContentShown+"').style.visibility='hidden'");
            eval("document.getElementById('"+which + "').style.visibility = 'visible'")
          }
          scrollContentShown = which
          scrollLimit = limit
      }

      function showobj(showobj) {
              if (n) eval("document." + showobj + ".visibility = 'show'")
              if (ie) eval(showobj + ".style.visibility = 'visible'")
      }

      function hideobj(hideobj) {
              if (n) eval("document." + hideobj + ".visibility = 'hide'")
              if (ie) eval(hideobj + ".style.visibility = 'hidden'")
      }