Confirm postback OnClientClick button ASP.NET

Question

<asp:Button runat="server" ID="btnUserDelete" Text="Delete" CssClass="GreenLightButton"
                           OnClick="BtnUserDelete_Click"
                           OnClientClick="return UserDeleteConfirmation();" 
 meta:resourcekey="BtnUserDeleteResource1" />

I have tried:

function UserDeleteConfirmation() {
        if (confirm("Are you sure you want to delete this user?"))
            return true;
        else
            return false;
}

and

function UserDeleteConfirmation() {
    if (confirm("Are you sure you want to delete this user?")) {
            __doPostBack(btnUserDelete, '');
    }

    return false;
 }

And none of them works.

make sure page validators are not getting fired... if validations are getting fired you will not able to submit the page.BTW code looks gud — Paritosh, Dec 27 '12 at 16:53
I know you found a solution but I posted an answer below that explains what was the underlying cause of this problem. — chrismay, Jun 05 '15 at 16:30

Hans Keﬆing · Accepted Answer · 2012-12-27T18:16:39.347

88

Try this:

<asp:Button runat="server" ID="btnUserDelete" Text="Delete" CssClass="GreenLightButton"
                       OnClick="BtnUserDelete_Click"
                       OnClientClick="if ( ! UserDeleteConfirmation()) return false;" 
 meta:resourcekey="BtnUserDeleteResource1" />

This way the "return" is only executed when the user clicks "cancel" and not when he clicks "ok".

By the way, you can shorten the UserDeleteConfirmation function to:

function UserDeleteConfirmation() {
    return confirm("Are you sure you want to delete this user?");
}

edited Dec 27 '12 at 18:16

answered Dec 27 '12 at 16:53

Hans Keﬆing

38,117
9
79
111

thanks) it works fine for me the only thing is left - to figure out why other scripts do not – makambi Dec 27 '12 at 16:59
I tried function UserDeleteConfirmation() { return confirm("Are you sure you want to delete this user?"); } It does not work ether – makambi Dec 27 '12 at 17:02
If updating to the shorter `UserDeleteConfirmation()`, you could then use `OnClientClick="return UserDeleteConfirmation();"` – Alex McMillan Dec 08 '16 at 01:01
1

@AlexMcMillan - no, the return might stop the submit action. At least in a LinkButton, it does (as that relies on further javascript, that would be ignored). See the answer by chrismay. – Hans Keﬆing Dec 09 '16 at 12:08
4

@HansKesting For crying out loud... why do Microsoft do that? This kind of stupid idea is all throughout asp - breaking standards and patterns that have been used for years for no reason. Microsoft technologies should be outlawed. – Alex McMillan Dec 11 '16 at 00:37
@HansKesting Nowadays `LinkButton` doesn't suffer from this condition anymore as it uses `href` attribute for `__doPostBack`, but `asp:Button` is still affected. – Michal Nawrocik Nov 06 '19 at 10:23

score 37 · Answer 2 · answered Jun 05 '15 at 16:25

There are solutions here that will work, but I don't see anyone explaining what is actually happening here, so even though this is 2 years old I'll explain it.

There is nothing "wrong" with the onclientclick javascript you are adding. The problem is that asp.net is adding it's on onclick stuff to run AFTER whatever code you put in there runs.

So for example this ASPX:

<asp:Button ID="btnDeny" runat="server" CommandName="Deny" Text="Mark 'Denied'" OnClientClick="return confirm('Are you sure?');" />

is turned into this HTML when rendered:

<input name="rgApplicants$ctl00$ctl02$ctl00$btnDeny" id="rgApplicants_ctl00_ctl02_ctl00_btnDeny" 
onclick="return confirm('Are you sure?');__doPostBack('rgApplicants$ctl00$ctl02$ctl00$btnDeny','')" type="button" value="Mark 'Denied'" abp="547">

If you look closely, the __doPostBack stuff will never be reached, because the "confirm" will always return true/false before __doPostBack is reached.

This is why you need to have the confirm only return false and not return when the value is true. Technically, it doesn't matter if it returns true or false, any return in this instance would have the effect of preventing the __doPostBack from being called, but for convention I would leave it so that it returns false when false and does nothing for true.

Thanks, this is the sort of thing that sends you off in circles. — Chris, Aug 23 '17 at 16:44

score 15 · Answer 3 · answered Feb 22 '13 at 14:29

15

You can put the above answers into one line like this. And you don't need to write the function.

    <asp:Button runat="server" ID="btnUserDelete" Text="Delete" CssClass="GreenLightButton"
         OnClick="BtnUserDelete_Click" meta:resourcekey="BtnUserDeleteResource1"
OnClientClick="if ( !confirm('Are you sure you want to delete this user?')) return false;"  />

answered Feb 22 '13 at 14:29

Praveen Mitta

1,408
2
27
48

1

I was getting javascript errors during the postback when calling a function, but using this approach was successful. – atjoedonahue Aug 12 '19 at 15:45

Kapil Khandelwal · Answer 4 · 2012-12-28T08:32:27.440

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>

score 5 · Answer 5 · answered Dec 27 '12 at 16:49

5

try this :

<asp:Button runat="server" ID="btnUserDelete" Text="Delete" CssClass="GreenLightButton" 
   onClientClick=" return confirm('Are you sure you want to delete this user?')" 
   OnClick="BtnUserDelete_Click"  meta:resourcekey="BtnUserDeleteResource1"  />

answered Dec 27 '12 at 16:49

Mahmoud Farahat

5,364
4
43
59

does the form postback at all? What do you mean by "Does not work?" – malkassem Dec 27 '12 at 16:53
Does not postback at all =/ – makambi Dec 27 '12 at 16:55
can, but with OnClientClick="UserDeleteConfirmation()" it postbacks fine on both of choises – makambi Dec 27 '12 at 16:58

score 5 · Answer 6 · answered Jun 21 '13 at 17:35

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";
    }
}

Validation in server, not in client – Kiquenet Mar 16 '16 at 15:24 — Kiquenet, Mar 16 '16 at 15:24

score 4 · Answer 7 · edited Jun 25 '15 at 14:32

4

try this : OnClientClick="return confirm('Are you sure ?');" Also set : CausesValidation="False"

edited Jun 25 '15 at 14:32

Mitat Koyuncu

928
8
20

answered Dec 27 '12 at 17:11

Srinivas

1,063
7
15

`CausesValidation="true"` and `OnClientClick` not compatible ? – Kiquenet Mar 16 '16 at 15:26

score 3 · Answer 8 · answered Apr 22 '15 at 16:53

3

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" />

answered Apr 22 '15 at 16:53

Vinicius

71
3

score 1 · Answer 9 · answered Jul 29 '15 at 13:56

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

score 0 · Answer 10 · answered Feb 12 '16 at 12:02

Try this:

function Confirm() {
    var confirm_value = document.createElement("INPUT");
    confirm_value.type = "hidden";
    confirm_value.name = "confirm_value";

        if (confirm("Your asking")) {
            confirm_value.value = "Yes";
            document.forms[0].appendChild(confirm_value);
        }
    else {
        confirm_value.value = "No";
        document.forms[0].appendChild(confirm_value);
    }
}

In Button call function:

<asp:Button ID="btnReprocessar" runat="server" Text="Reprocessar" Height="20px" OnClick="btnReprocessar_Click" OnClientClick="Confirm()"/>

In class .cs call method:

        protected void btnReprocessar_Click(object sender, EventArgs e)
    {
        string confirmValue = Request.Form["confirm_value"];
        if (confirmValue == "Yes")
        {

        }
    }

score 0 · Answer 11 · answered Feb 24 '21 at 11:57

I know this is old and there are so many answers, some are really convoluted, can be quick and inline:

<asp:Button runat="server" ID="btnUserDelete" Text="Delete" CssClass="GreenLightButton" OnClick="BtnUserDelete_Click" OnClientClick="return confirm('Are you sure you want to delete this user?');" meta:resourcekey="BtnUserDeleteResource1" />

Confirm postback OnClientClick button ASP.NET

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