<script language="javascript" src="jquery-1.2.3.min.js"></script>
<script language="javascript">
function loader(page,param)
{
	alert($("#content").css("display"));
	$("#content").hide("slow");
	$.post(page,{ param1: param},onAjaxSuccess);
	function onAjaxSuccess(data)
	{
		$("#content").append(data);
		$("#content").show("slow");
	}
}
</script>
<input type="text" id="t"><input type="button" onclick="loader('ajax.php',document.getElementById('t').value)">
<span id="content"></span>