function showCommentList(list_id, doc_id){
	var formName = 'comment_add_form';
	var mydate = new Date();
	var mytime = mydate.getTime();
	var requestBaseUrl = '/tech/ajax_doc_comments/index/json/' +doc_id+ '?a=1';
	var requestUrl = requestBaseUrl;
	var method = 'post';
	var query_param = '';
	new Ajax.Request(requestUrl + '&t=' + mytime, {
		method: method,
		parameters: query_param,
		requestHeaders: {'If-Modified-Since': 'Thu, 01 Jun 1970 00:00:00 GMT'},
		
		// 結果コンテンツの反映
		onSuccess: function(request){
			$(list_id).hide();
			$(list_id).innerHTML = request.responseJSON.contents;
		},
		onComplete: function(request){
			$(list_id).appear();
		}
	});
}