<SCRIPT LANGUAGE="JavaScript">

<!--

function limitNum(obj) {

    if(obj.value.replace(/[\d+]/ig,"").length>0) {

        alert('请输入数字')

    }

}

//-->

</SCRIPT>



<input name="textfield1" type="text" id="textfield1" style="width:60;" onKeyup="limitNum(this)" />
<!--<asp:textbox name="dealtime" type="text" size="25" id="dealtime" runat="server" Width="42px" MaxLength="5" onpropertychange="limitNum(this)"></asp:textbox>-->