help,在线等待

<body>
<form id="form1" runat="server">
<TEXTAREA id="ta" style="WIDTH: 709px; CLIP: rect(0px auto auto 0px); HEIGHT: 353px" rows="22" cols="86" wrap="soft"></TEXTAREA> 
<INPUT id="t1" type="text"> <INPUT type="button" value="发言"          onclick="ta.innerText+=t1.value;t1.value=''">
</form>
</body>