function index_combo(texto,combo){
for (i=0; i<document.getElementById(combo).length; i++)
	{
	  document.getElementById(combo).selectedIndex = i;
	  if (document.getElementById(combo).value == texto)
		{
		  break;
		}
	}
	if (texto=='null')
	  document.getElementById(combo).selectedIndex = 0;
}

//función para sólo dejar ingresar números a una objeto de formulario
var nav4 = window.Event ? true : false;
function acceptNum(evt){ 
	// NOTE: Backspace = 8, Enter = 13, '0' = 48, '9' = 57 
	var key = nav4 ? evt.which : evt.keyCode; 
	return (key == 45 || key <= 13 || (key >= 48 && key <= 57));
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}
function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}


function MM_findObj(n, d) { //v4.01
	  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
		d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
	  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
	  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
	  if(!x && d.getElementById) x=d.getElementById(n); return x;
	}
	
function MM_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
	if (val) { nm=val.name; if ((val=val.value)!="") {
	  if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
		if (p<1 || p==(val.length-1)) errors+='- '+nm+' Debe contener una dirección de correo valida.\n';
	  } else if (test!='R') { num = parseFloat(val);
		if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
		if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
		  min=test.substring(8,p); max=test.substring(p+1);
		  if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
	} } } else if (test.charAt(0) == 'R') errors += '- '+nm+' es obligatorio.\n'; }
  } if (errors) alert('Se presentaron los siguientes errores:\n'+errors);
  document.MM_returnValue = (errors == '');
}

  function abrir(pag,ancho,alto,posx,posy){
	  emergente = window.open(pag, "ventana","status=yes,width="+ancho+", height="+alto+",scrollbars=no,location=no,toolbar=no,directories=no,menubar=no,left="+posx+",top="+posy+"");        
	  emergente.focus();
    }

	function cambiar_pagina(operacion){ 
		var pagina = document.form1.pagina.value;
		var num_pag = document.form1.num_pag.value;
	
		switch(operacion)	{
		case "primero":
			document.form1.pagina.value = 1;
			document.form1.submit();
		break;
		
		case "anterior":
			if (pagina != 1){
				document.form1.pagina.value = parseInt(document.form1.pagina.value)-1;
				document.form1.submit();
				}
			else
				alert("No hay página anterior");	 
		break;
	
		case "siguiente":
			if (pagina != num_pag){
				document.form1.pagina.value = parseInt(document.form1.pagina.value)+1;
				document.form1.submit();
				}
			else
				alert ("No hay página siguiente");	 		
		break;
		
		case "ultimo":
			document.form1.pagina.value = num_pag; 
			document.form1.submit();
		break;
	
		}
	
	}

function nuevoAjax() { 
	var xmlhttp=false; 
	try { 
		xmlhttp=new ActiveXObject("Msxml2.XMLHTTP"); 
	}
	catch(e) { 
		try { 
			xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); 
		} 
		catch(E) { xmlhttp=false; }
	}
	if (!xmlhttp && typeof XMLHttpRequest!='undefined') { xmlhttp=new XMLHttpRequest(); } 
	return xmlhttp; 
}