function MM_changeProp(objName,theProp,theValue) { //v3.0
  var obj = MM_findObj(objName);
  if (obj && (theProp.indexOf("style.")==-1 || obj.style)) eval("obj."+theProp+"='"+theValue+"'");
}

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 vaciarCombo(obj)
{
	for (var i = obj.options.length - 1; i >= 0; i--) {
		obj.options[i] = null;
	}
		obj.options[0] = new Option("","",false,false);
}

var wndVar;
function abrirSubVentana(url, nombre, ancho, alto)
{
	w = (screen.availWidth - ancho) / 2;
	h = (screen.availHeight - alto) / 2;
	features = "left="+w+",top="+h;
	features += ",width=" + ancho + ",height=" + alto + ",toolbar=no,menubar=no,resizable=yes,location=no,directories=no,status=no,scrollbars=yes,copyhistory=no";
	if(wndVar !=null)
	{
		wndVar.close();
		wndVar=null;
	}
	wndVar = window.open(url, nombre, features)
	wndVar.focus()
	return wndVar;
}

function mostrarImagen(url)
{
	abrirSubVentana('mostrarImagen.php?fichero=' + url, 'Imagen', 700, 550);
}