Javascript - How To Do Validation Before Postback

Mar 28, 2011

I have custom control with ASP.Net validators.

writer.AddAttribute(HtmlTextWriterAttribute.Onclick, "javascript:return DoSmth();");

function DoSmth() {
var cBox = confirm("Are you sure?");
if (!cBox) {
return false;
else {
//Invoke validation

When I push button submit, I call confirm box. If I press cancel - all right. But if I press ok, I need to do validation. How can I stop postback and do valiadation?

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C# - Client-Side Validation Prvent Manually Postback By JavaScript Eval ()

Mar 8, 2010

I encouter some postback issue when using GetPostBackEventReference. Here is the Scenario:I have a javascript modal popup dialog and got a button in this modal dialog which used to select things (this is NOT an asp:button control)

When this javascript dialog HTML button is clicked, it will call the MS AJAX web service call by the javascript: eval() method. And this MS AJAX web service call is dynamically generated. So the code is like this:

var serviceCall = svcCall + "(" + parameters + ")"; //dynamically generate the MS AJAX web service call here

//use eval to trigger the MS AJAX web service call

As you may all know, after complete the MS AJAX web service, you can define a callback function to handle the completion:

function OnComplete(result, userContext, methodName) {

//force to call postback manually
eval($(userContext[0]).val()); [code]...

As you can see, this is how I bound the asp:button (i.e. btnSelectUser) 's Click Event to the asp:hiddenfield using the GetPostBackEventReference, and set the registerForEventValidation argument to false. I have also tried to use different ValidationGroup and set the CausesValidation to false.In summarize, I bound the asp:button's Click PostBackEventReference(i.e. __doPostback(....)) to the asp:hidden field's Value attribute, and using javascript eval() to eval this hidden field's value in order to manually trigger postback.

p.s. the btnSelectUser is an asp:button control and used to call out the javascript modal dialog.

Ok, here is the Problem:In the same page, there is some asp:validator, e.g. and , and of coz, when the page run into error, this validator and callout will display to the user. e.g. When the user didn't fill in anything and submit the form, the ValidatorCalloutExtender will display a ballon and tell the user. Imagine one of this ballon/validatorCalloutExtender come out and on top of your screen at the moment.

Then you click the btnSelectUser (asp:button) to show the javascript modal dialog, and in the dialog, you Add some users, and once you hit the SELECT button inside this modal dialog, a MS AJAX web service is trigger as mentioned above, and once this web service is complete, it eval() the asp:hidden field's value (i.e. __doPostback(...))......and do the postback manually.

However, because of the validatorCalloutExtender ballon has display, it somehow cannot trigger the postback in this way, but when I close the ballon/validatorCalloutExtender, the manual postback using eval() is just working fine. Even more strange is that, when the ballon is displayed, the first time I click the SELECT button inside this modal dialog it doesn't fire the postback, however, if I do the same thing again (i.e. open up the javascript dialog, and choose some users, then click the SELECT button again). It able to do the manual postback....and I don't understand why the first time doesn't work.

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Forms Data Controls :: Javascript Validation For Assigning Validation Group To Validation Summary On Datalist Item Click?

Dec 25, 2010

I am using one datalist control for uploading multiple images.I hv used one Asp:FileUplaod Control and one button in one itemtemplate.I am using reqired field validator and regular expression validator for file upload cntrl I am assigning validation group for both of them on ItemDataBound event of my datalist so that each upload cntrl hv same validaton group as required field and regular expression validator.Now what i want to do is - i want to show my error message in validation summary which is right at the top of the page.I want one know how to write javascript that will assign validation group of my control in datalist on which i click ?

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Web Forms :: How To Disable The Code Behind Validation When Javascript Validation Is Present

Jul 25, 2010

How can I disable the code behind validation when javascript validation is present? Then if there is no javascript enabled then the code behind validation will do its thing. What I notice is that it's reading the code behind valdiation not the javascript.

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Javascript - Perform A Validation To Check Whether A TextBox Value Is Empty On Dropown List Selected Index Change Using Validation Controls?

Jan 19, 2011

I need to perform a validation to check whether a TextBox value is empty on Dropown list selected Index change using validation controls in

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Web Forms :: Validation And Postback - Error "Invalid Postback Or Callback Argument"

Sep 21, 2009

I have two server controls on page, both have buttons what must postback. One control uses validation and work ok. Other causes error: Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them.

If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. I`ve tried to set CausesValidation="False" Both controls are added dynamicaly so they do not know about other.

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How To Go For Custom Validation Control And When To Do Validation In Javascript

Mar 12, 2010

When to go for custom validation control and when to do validation in javascript? What are pros and cons of each of them?

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Web Forms :: How To Perform Click (postback From JavaScript) On The Button From JavaScript In Opera

Sep 3, 2009

i have a TextBox and Codebehind if the page i added following, to register my script:

protected void Page_PreRender(object sender, EventArgs e) {
Page.ClientScript.RegisterStartupScript(Page.GetType(), "textBoxSet", "textBoxSet(document.getElementById('" + QueryTextBox.ClientID + "'));", true);


but still, Opera has no affect of executing this, how to perform click on the button, i mean to perform a postback from JavaScript with the target of the searchButton ?

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Javascript - Client Side Validation And Server Side Validation In Java Script And Respectively ?

Sep 6, 2010

want to know that can we validate a control which is out side a form element in side validation)and outside a form element in html(client side validation) let's take a closer look

<input type="text" name="first name"/>

can we apply clien side validation on above text box by java script ?in

<form runat="server">
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

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Javascript - Postback And Get Value From Html In That Postback?

Feb 4, 2011

I have a js function

// do a postback here and get the id on the server side

I need to send the id to the server, how could I do this?

any way will do, using additional/hidden controls anything

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Forms Data Controls ::Postback Of Page Using JavaScript Postback's Slow Down The Page?

Sep 22, 2010

I'm at my wits end on this one looked/Searched/Played/Experimented and I need your help if you can.This page is going to be primarily used on a mobile device using Win Mobile 5 Need to Accomplish:Prevent Postback(serverside) of Page using JavaScript (Postback's slow down the page on mobile device)


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.Net Validation Controls Work *before* The First Postback?

Jan 4, 2011

We are investigating using ASP.Net validations for client side validating. Is it possible to get the client side validators to work before an initial postback?

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Postback Validation Causes An Alert Dialog To Be Displayed?

Jun 4, 2010

For some strange reason an alert dialog with the text title "Message From Web page" and message "-" displays when posting back a for with validation. There are no custom validation scripts that display an alert window. I am debgging javascript using IE development toolbar? Is it possible to break into the code that displays the alert box? so far I have been unable to do so.

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Web Forms :: Validation Summary Appears After Postback?

Mar 8, 2011

i have many validators but one validator RFVRIDDORReferenceId is enabled and disabled through javascript. because txtReferenceId is shown when something is selected from a dropdownlist. initially it is disabled. everything was working fine until i implemented EDIT functionality in which through an ID i need to load page and show everything...on serverside i enabled

RFVRIDDORReferenceId.Enabled = true;

if ReferenceId database field had value in it. other wise it stays like that. after loading the information on page and disable RFVRIDDORReferenceId through client save button and everything will be updated but when page comes back validation summary has

Following errors occured
> ReferenceId is required

it displays in red i dont know why it is doing it....(postback itself shows that all validators were true). is there any reason?

does validator validate themselve after postback? if yes then why does not remaining validators shows error message?

PS: its a required field validator and there are many other but validation summary shows only for this validator.

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Postback To Control's Parent - Validation Of Viewstate MAC Failed / How To Fix It

Mar 24, 2011

I have a bit of javascript that presents a modal to the user with the rest of the page "grayed out." Pretty common these days. The modal allows you to specify a URL which then uses AJAX to serve and display. What I need is that when the control posts back, it posts back to the parent page, not the modal page. To attempt this, I used javascript to alter the target of the modal page's form element to the parent page's URL. When I try this I get the following error:

Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

This is done locally and as of now, the app will never be on a cluster. I think this has to do with the validation process and .NET doesn't like that I've changed the target. Anyone know a way around this? I really need this to work how I described.

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How To Prevent Loading Of Data When Postback Fails Validation

Feb 5, 2010

I'm trying to prevent data from loading on the page when its needed.

Currently, I check the IsPostBack bool to prevent loading data in my user controls which allows the data to be loaded when the page is initially requested.

However, if my page fails validation and the page is sent back to the user with error messages, my user controls no longer have data in them because the initial request was a postback.

One solution is to have a flag in every user control (IsFailedPostBack) to force them to reload their data. Is there a better way?

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Invalid Postback Or Callback Argument, Event Validation Is Enabled

Jul 27, 2010

I have a TabContainer, within a tab, i have a gridview, within the gridview i have a ImageButton. When I click on the ImageButton, I will call a javascript. The javascript will call a Hidden Button click. This hiddenbutton is the TargetControl of the Modalpopup so that when I click on the ImageButton, modalpopup is trigger. The Popup panal, Hidden Button and ModalPopupExtender below:

<asp:Panel ID="panEditAccessLog" runat="server" CssClass="gc_modalPopup" Style="display: none" BorderWidth="0px">
<table width="400px">
<td width="150" height="20">
Employee ID:

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C# - Validation Controls In User Control Not Stopping Page Postback?

Jan 28, 2011

I have a asp button and a user control containing custom validator in it when i click the button that is present on the page not inside the usercontrol, the user control client side validation occurs and displays the javascript method regarding data entry failure but when i click the javascript alert box ok button, the postback gets occured automatically i want to stop the postback if the user control contains invalid data in iother words the postback get occured only when the user control contains the valid data.

I have already done this type of coding in javascript:

function CheckTimeRangeTo_9(sender, args) {
var e = document.getElementById('<%= ddTimeTableTo_9.ClientID %>');
var totalToTimeInMins = CalculateTotalMinutes(e.options[e.selectedIndex].value);
var totalFromTimeInMins = CalculateTotalMinutes(args.Value);


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Web Forms :: Stop Postback After Imagebutton Click On Page Validation Error?

Nov 20, 2010

i have some textbox that i validate with a customvalidator control (only, and must be, server side function) and i have an imagebutton control for submit.I must stop the postback if there are some errors in the validation function.I set the validation property argumets.isvalid = false in the customvalidator function but doesn't work, the postback continue.i have tried to set the imagebutton property postbackurl = "" in the validation function but doesn't work.

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Web Forms :: Validation Summary To Maintain Prior Error Messages During The Postback?

Jun 23, 2010

I have the following user control:


This control is used multiple times on one aspx page. The issue is that each time an instance of the control is validated due to a text change any prior error messages are cleared from the validation summary. I want the validation summary to maintain prior error messages during the postback.

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Web Forms :: Create Via C# In An Event Causing Page Validation To Occur On Postback?

Feb 14, 2011

I'm having trouble with an image button I create via c# in an event causing page validation to occur on postback. The CausesValidation attribute is set to false at time of creation in the event. I also wire up the Click event in the page_init with postback so not to loose the event handler if the page posts another way. Here is the code I'm using in the click event of a Button. I've also tried to enable and disable viewstate for the button with no luck. What am I missing here that continues to fire page validation in the Click of this imagebutton?


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AJAX :: Clientside Validation Stops Working In Updatepanel After Initial Postback?

Dec 18, 2009

I have a regularexpression and requiredfield validator and submit button in the updatepanel. I show this in a modal dialog and user can keep posting data to server until he closes the dialog. What I'm seeing is that if the input is invalid, the clientside validation prevents the postback from happening. So this works as excepted. But once a postback happens (when the user enters proper data), the subsequent postbacks are not aborted even if the clientside validation has failed. The clientside validation is taking place becuase I see the error messages but the postback still happens even if the Page_IsValid is false. This postback does not happen in the initial submit if the clientside validation fails. How do I prevent subsequent asyncpostbacks if the validation fails on the client? The problems seems to be the updatepanel is causing some of the javascript hookups to stop working after postback.

I tried hooking into the ajax beginrequest call and aborting the postback but that's not working either. Also Onclientclick event on the submit button stops firing after the initialpostback.

if (typeof(Page_IsValid) !=
"undefined" && !Page_IsValid) {var prm = Sys.WebForms.PageRequestManager.getInstance();

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Web Forms :: Invalid Postback Or Callback Argument. Event Validation Is Enabled Using <pages EnableEventValid?

Oct 4, 2007

I have the following error message come up whenever I click this button in my DataList.



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Radiobuttonlist - Javascript Validation For Asp

Feb 16, 2011

I am using a radiobuttonlist.

<asp:RadioButtonList ID="rbtnAEreq" RepeatDirection="Horizontal" runat="server">
<asp:ListItem Text="Yes" Value="true"></asp:ListItem>
<asp:ListItem Text="No" Value="false"></asp:ListItem>

on buttonclick event i want to validate the radiobuttonlist. My condition is either yes or no should be selected. How to do it in javascript.

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Jquery - Using MVC Validation In Javascript

Feb 2, 2011

I am currently looking a valiadation controls in javascript and ASP.NET and have come across the new MVC "jquery.validate.unobtrusive.js" which appears to use the data tags in the HTML to do the validation, is it possible to use these in standard ASP.NET (none MVC) as my logic seems to indication you can (by adding the appropriate data tags) but I can't find any referrance to using the library outside MVC

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.NET Javascript And Postback?

Apr 3, 2011

I have a page located in an iframe of another page. It calls a js function like this:

function F(a)
parent.document.getElementById('A').value = a;[code]....

It results in page reloading. How can I prevent it? Previously I've used return false; and it worked. But not in this case.

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Web Forms :: Validation In Javascript Does Not Seem To Work?

Jan 17, 2011

I don't know what the problem is a get the message object required??


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C# - How To Handle Validation When JavaScript Is Disabled

Apr 4, 2011

I'm using some of the typical ASP.NET's Validation Controls in my website. Now I'm trying to disable the JavaScript in my browser to test my application and of course the Validation Controls no longer works. I think it's best to try to make them work using one of the solutions down here instead of reinvesting the wheel and build a validation layer for the page or my objects -Am I thinking right?-

What do you think of these options and why:

Include in clicked button's event a code to check if the page is valid and if not explicitly call the Page.Validate(); method Check if whether the JavaScript is enabled and if not I should call Page.Validate();

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Javascript - Validating Against Checkbox And Validation

Jan 19, 2011

I'm using validation controls which work fine. I've since introduced an HTML checkbox which should be ticked before the form can be submitted. My function for this reads as follows:

function terms(form) {
var terms = document.getElementById("chkTerms").checked;
var errorsArray = new Array();
if (terms == false) {
//alert("Terms not checked (works)");
errorsArray.push("You must agree to the terms and conditions.");
if (errorsArray.length) {
document.getElementById("termsOutput").innerHTML = errorsArray.join("
") + "<br />";
return false;
else {
document.getElementById("termsOutput").innerHTML = "";

It is called as follows:

<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClientClick="return terms(form)" />

The problem I have is seems I can either use the validation OR the custom checkbox validation I wrote. After the form posts however, the validation fires!

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Validation - Javascript For Two Checkboxes In Aspx

Jul 12, 2010

I have one textbox and two checkboxes with a submit button. I want to put a customvalidator which shall call a javascript for the following condition -

If textbox.value > 0 then checkbox1 = checked or checkbox2 = checked. If neither checkboxes checked when textbox.value > 0 then raise error.

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