用jQuery中的mouseEnter控制asp中Timer控件的开关，不好使。求大神看看哪有问题

   <script type="text/javascript">
        $(document).ready(function () {
            $("pnl_chat").mouseenter(function () {
                document.getElementById('<%=Timer1.ClientID%>').disabled=true;
                
            });
            $("pnl_chat").mouseleave(function () {
                document.getElementById('<%=Timer1.ClientID%>').disabled = false;
               
            });            
        });
</script>
 <div style="text-align: left">
            <asp:Timer ID="Timer1" runat="server" Interval="3000" OnTick="Timer1_Tick">
            </asp:Timer>