function mostrar_login(){  

  if ($('form_login').getStyle('display')=="none" || $('form_login').getStyle('opacity')==0)
  {

		$('form_login').setStyle('filter: Alpha(opacity=0); -moz-opacity: 0; -khtml-opacity: 0;');
    $('form_login').setStyle({
      display: 'block'
    });
    
			

		if (IE6()==true)
		{
      	//var iframe = document.createElement('iframe'); 
				var iframe = new Element('iframe'); 
				iframe.id = 'form_login_iframe';
				iframe.style.height = $('form_login').getDimensions().height;		            
				$('cabecera').appendChild(iframe);
				$('form_login_iframe').setStyle('filter: Alpha(opacity=0); -moz-opacity: 0; -khtml-opacity: 0;');
		    $('form_login_iframe').setStyle({
  		    display: 'block'
    		});
		}
		new Effect.Opacity('form_login', { from: 0, to: 1});    	
		//if (IE6())
			//new Effect.Opacity('form_login_iframe', { from: 0, to: 1});   
			$('area_privada').className = "areaprivada_close"; 
  }
  else
  {
		new Effect.Opacity('form_login', { from: 1, to: 0, duration: 0.5 });		 
		if (IE6()){
			//new Effect.Opacity('form_login_iframe', { from: 1, to: 0});   
			setTimeout('deleteIframes()', 300 );
		}
		$('area_privada').className = "areaprivada";
  }
}


function IE6() {
  Prototype.Browser.IE6=parseInt(navigator.userAgent.substring(navigator.userAgent.indexOf("MSIE")+5))==6;
  if (Prototype.Browser.IE6)
    return true;    
  return false;
}


function deleteIframes () {
	  var iframes = $$('iframe');	  	  
	  iframes.each(function(s) {Element.remove(s); });
	}
	
function mostrar_banner(capa)
{
		  $('overlay').style.display = 'block';
		  $(capa).style.display = 'block';

		  document.getElementsByTagName("html")[0].style.overflow = "hidden";
		  //Hay que aņadir el evento onkeypress

		  document.observe('keydown', function(event){ 

		    if (Event.KEY_ESC == event.keyCode)
		    {
		      cerrarCapa(capa);
		    }			  
		  });
		  
		  $('overlay').observe('click', function(event){ 
		      cerrarCapa(capa);		    
		  });		  
}

function cerrarCapa(capa)
{
  $('overlay').style.display = 'none';
  $(capa).style.display = 'none';

  document.getElementsByTagName("html")[0].style.overflow = "auto";
}