updatepanel not supporting textbox autopostback event(ontextchanged event) for chacking user entered data.
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div class="form-group has-feedback has-feedback-left">
<asp:Label ID="Label6" runat="server" CssClass="control-label col-sm-2" Text="phoneno:"></asp:Label>
<div class="col-sm-10">
<asp:TextBox ID="usrphonenotxt" runat="server" CssClass="form-control" ValidationGroup="regv"
ToolTip="phoneno" TextMode="Phone" AutoPostBack="true" OnTextChanged="usrphonenotxt_TextChanged"></asp:TextBox>
<i class="form-control-feedback glyphicon glyphicon-phone"></i>
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ValidationGroup="regv"
ErrorMessage="10-digits phoneno" ControlToValidate="usrphonenotxt" ValidationExpression="\d{10}"
Display="Dynamic" ForeColor="Red"></asp:RegularExpressionValidator>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ValidationGroup="regv"
ErrorMessage="Fill phoneno " ControlToValidate="usrphonenotxt" Display="Dynamic"
ForeColor="Red"></asp:RequiredFieldValidator>
</div>
</div>
</ContentTemplate>
</asp:UpdatePanel>
Another problem is when i add autopostback to textbox the regularexpression is not working proparly because both event raise at time.How can we handle this situation.