Alert on navigation to other tab

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:ScriptManager runat="server"></asp:ScriptManager>
    <script type="text/javascript" language="javascript">
        var changedElements = new Array();
        var previousTabIndex=null;
        function notification(obj, args) {
            if (previousTabIndex==null || previousTabIndex==0) {
                var msg = "Text changed in these elements ";
                var length = changedElements.length;
                for (i = 0; i < length; i++) {
                    msg = msg + ", " + changedElements[i].id;
                }
                if (msg.length > 31) {
                    alert(msg);
                }
                changedElements.length = 0;
            }
            previousTabIndex = obj.get_activeTabIndex();
        }
        function addToNotify(textbox) {
            changedElements.push(textbox);
        }
    </script>
    <asp:TabContainer  OnClientActiveTabChanged="notification" ID="TabContainer1" runat="server" ActiveTabIndex="0">
        <asp:TabPanel runat="server" HeaderText="TabPanel1" ID="TabPanel1">
            <ContentTemplate>
                <asp:TextBox runat="server" ClientIDMode="Static"   ID="Text101"></asp:TextBox>
                <asp:TextBox runat="server" ClientIDMode="Static"   ID="Text102"></asp:TextBox>
                <asp:TextBox runat="server" ClientIDMode="Static"   ID="Text103"></asp:TextBox>
                <asp:Button runat="server" ID="button101" />
            </ContentTemplate>
        </asp:TabPanel>
       <asp:TabPanel runat="server" HeaderText="TabPanel2" ID="TabPanel2">
            <ContentTemplate>
                <asp:TextBox runat="server" ID="TextBox1"></asp:TextBox>
            </ContentTemplate>
        </asp:TabPanel>

    </asp:TabContainer>

</asp:Content>

protected void Page_Load(object sender, EventArgs e)
 {
     Text101.Attributes.Add("onblur", "addToNotify(this);");
     Text102.Attributes.Add("onblur", "addToNotify(this);");
 }