function unmessage()
{
	Effect.Fade('apear-div');
}

function message()
{
	Effect.Appear('apear-div');
}

function stepToSession(trophee_id, lang)
{
	if (document.getElementById('apear-div').style['display'] != "none")
		unmessage();
	var flag = 0;
	var xhr = getXhr();
	var form_step = document.getElementById('choose_step');
	var form_session = document.getElementById('choose_session');
	var step_id = form_step.options[form_step.selectedIndex].value;
	xhr.onreadystatechange = function()
	{
		if (xhr.readyState == 4)
			{
				if  (xhr.status == 200)
				{
					response = clean(xhr.responseXML.documentElement);
					sessions = response.getElementsByTagName('session');
					for (i = 0; i < form_session.options.length; i++)
						form_session.options[i] = null;
					for (i = 0; i < sessions.length; i++)
					{
						form_session.options[i] =
							new Option('['+sessions[i].getElementsByTagName("session_remain")[0].firstChild.nodeValue+']   '+sessions[i].getElementsByTagName("session_time")[0].firstChild.nodeValue,
									   sessions[i].getElementsByTagName("session_id")[0].firstChild.nodeValue);
						if (sessions[i].getElementsByTagName("session_remain_nb")[0].firstChild.nodeValue == "NONE")
							flag = 1;
					}
					if (flag == 1)
						message();
				}
			}
	}
	xhr.open("POST","/scripts/subscribe.script.php", true);
	xhr.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
	xhr.send('trophee_id='+trophee_id+'&step_id='+step_id+'&lang='+lang);

}