动态改变并显示文本域的高度

// 设置textarea的高度
function SetAutoHeight(obj)
{
    // 取原始高度
    if (obj.getAttribute("oldHeight", 0) == null)
    {
        obj.setAttribute("oldHeight", obj.style.pixelHeight, 1);
    }
    */
    oldHeight=obj.getAttribute("Height", 0);
    
    if (obj.scrollHeight>oldHeight)
    {
        obj.style.pixelHeight=obj.scrollHeight+4;
    }
    else
    {
        obj.style.pixelHeight=oldHeight;
    }
}

<asp:textbox id="txtMemo" runat="server" Width="635px" onpropertychange="SetAutoHeight(this);"
                TextMode="MultiLine" Height="38px" Rows="4"></asp:textbox>(2000字节)


然后加载时：
<script language="javascript" type="text/javascript">
var objArea=document.getElementById("txtMemo");
if(objArea.scrollHeight > 38)
{
    objArea.style.posHeight=objArea.scrollHeight;
}
</script>