验证文本框只能输入数字兼容FF,IE

<asp:TextBox ID="txtId" runat="server" style="ime-mode:disabled" onkeydown="myKeyDown(event)" MaxLength="5" ></asp:TextBox>

<script type="text/javascript">
    function myKeyDown(myEvent) {
        var k;
        if (window.event)
            k = myEvent.keyCode;     //IE
        else
            k = myEvent.which;     //firefox
        //alert(k);
        ////alert(key);

        if ((k == 46) || (k == 8) || (k == 189) || (k == 109) || (k == 190) || (k == 110) || (k >= 48 && k <= 57) || (k >= 96 && k <= 105) || (k >= 37 && k <= 40))
        { }
        else if (k == 13) {
            if (window.event)
                myEvent.keyCode = 9;
            else
                myEvent.which = 9;
        }
        else {
            //window.event.returnValue = false;
            if (document.all)
                myEvent.returnValue = false; //ie
            else
                myEvent.preventDefault(); //ff
        }
    }
</script>