var http_request = false;
	
function getTopicList(tcId)
{
	http_request = false;
	if (window.XMLHttpRequest)
	{   // Mozilla, Safari,...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType)
		{
			http_request.overrideMimeType("text/xml");
			// See note below about this line
		}
	}
	else if (window.ActiveXObject)
	{	// IE
		try
		{
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch (e)
		{
			try
			{
				http_request = new ActiveXObject("Microsoft.XMLHTTP");
			}
			catch (e)
			{
			}
		}
	}
	if (!http_request)
	{
		return false;
	}
	http_request.onreadystatechange = updateTopicList;
	http_request.open('GET', "/index.php?action=poemTopicList&tcId=" + tcId, true);
	http_request.send(null);
}

function updateTopicList ()
{
	if (http_request.readyState == 4)
	{
		if (http_request.status == 200)
		{
			RequestData = http_request.responseText.split("=>");
			var selectTopicList = document.getElementById("selectTopicList");
			while (selectTopicList.childNodes.length > 0)
			{
				selectTopicList.removeChild(selectTopicList.firstChild);
			}
			for (var i = 0; i < RequestData.length; i += 2)
			{
				if (!RequestData[i])
				{
					break;
				}
				var newOption = document.createElement("option");
				newOption.value = RequestData[i];
				newOption.innerHTML = RequestData[i + 1];
				selectTopicList.appendChild(newOption);
			}
			//document.getElementById("selectCity").innerHTML = http_request.responseText;
		}
		else
		{
			return false;
		}
	}
}