Confirm postback OnClientClick button ASP.NET

Answer 1

Try this:

<asp:Button runat="server" ID="btnDelete" Text="Delete"
   onClientClick="javascript:return confirm('Are you sure you want to delete this user?');" OnClick="BtnDelete_Click" />

Answer 2

The code is like this:

In Aspx:

<asp:Button ID="btnSave" runat="server" Text="Save" OnClick="btnSave_Click" CausesValidation=true />

in Cs:

protected void Page_Load(object sender, System.EventArgs e)
{
     if (!IsPostBack)
     {
         btnSave.Attributes["Onclick"] = "return confirm('Do you really want to save?')";          
     }
}

protected void btnSave_Click(object sender, EventArgs e){
    Page.Validate();
    if (Page.IsValid)
    {
       //Update the database
         lblMessage.Text = "Saved Successfully";
    }
}

Answer 3

This is a simple way to do client-side validation BEFORE the confirmation. It makes use of the built in ASP.NET validation javascript.

<script type="text/javascript">
    function validateAndConfirm() {
        Page_ClientValidate("GroupName");  //'GroupName' is the ValidationGroup
        if (Page_IsValid) {
            return confirm("Are you sure?");
        }
        return false;
    }
</script>

<asp:TextBox ID="IntegerTextBox" runat="server" Width="100px" MaxLength="6" />
<asp:RequiredFieldValidator ID="reqIntegerTextBox" runat="server" ErrorMessage="Required"
    ValidationGroup="GroupName"  ControlToValidate="IntegerTextBox" />
<asp:RangeValidator ID="rangeTextBox" runat="server" ErrorMessage="Invalid"
    ValidationGroup="GroupName" Type="Integer" ControlToValidate="IntegerTextBox" />
<asp:Button ID="SubmitButton" runat="server" Text="Submit"  ValidationGroup="GroupName"
    OnClick="SubmitButton_OnClick" OnClientClick="return validateAndConfirm();" />

Source: Client Side Validation using ASP.Net Validator Controls from Javascript

Answer 4

Using jQuery UI dialog:

SCRIPT:

<link rel="stylesheet" href="http://code.jquery.com/ui/1.9.2/themes/base/jquery-ui.css" />
<script src="http://code.jquery.com/jquery-1.8.3.js"></script>
<script src="http://code.jquery.com/ui/1.9.2/jquery-ui.js"></script>
<script>
 $(function () {

            $("#<%=btnUserDelete.ClientID%>").on("click", function (event) {
                event.preventDefault();
                $("#dialog-confirm").dialog({
                    resizable: false,
                    height: 140,
                    modal: true,
                    buttons: {
                        Ok: function () {
                            $(this).dialog("close");
                            __doPostBack($('#<%= btnUserDelete.ClientID %>').attr('name'), '');
                        },
                        Cancel: function () {
                            $(this).dialog("close");
                        }
                    }
                });
            });
 });
</script>

HTML:

<div id="dialog-confirm" style="display: none;" title="Confirm Delete">
    <p><span class="ui-icon ui-icon-alert" style="float: left; margin: 0 7px 20px 0;"></span>Are you sure you want to delete this user?</p>
</div>