function expandir_formulario(f){

	if (f.usuario_mayorEdad.checked){

		document.getElementById('fecha').style.display='block';
    document.getElementById('fecha').style.visibility='visible';
	}else{

		document.getElementById('fecha').style.display='none';
    document.getElementById('fecha').style.visibility='hidden';
	}
}

function sacarModal(){

	$('#modal_window').css('display','');

	  $('#layerbg').fadeIn(900, function(){

			$('#modal_window').animate({'top':$("html").scrollTop()+150},600)
	  })

}

function cerrarModal(){

	$('#modal_window').css('display','none');
	$('#modal_window').css('top','-600px');
	$('#layerbg').fadeOut(400);
  $('html, body').animate({scrollTop:1100}, 'slow');


}