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Disabling the button on the client side prevents the postback

There are two issues here:

Also, the OnClientClick code runs even if ASP.NET validation fails, so it's probably a good idea to add a check for Page_IsValid. This ensures that the button will not be disabled if validation fails.

OnClientClick="(function(button) { setTimeout(function () { if (Page_IsValid) button.disabled = true; }, 0); })(this);"

It's neater to put all of this JavaScript code in its own function as the question shows:

OnClientClick="disable(this);"

function disable(button) {
    setTimeout(function () {
        if (Page_IsValid)
            button.disabled = true;
    }, 0);
}

To overcome this, disable the button on the server side. For example, in the OnClick event handler:

OnClick="Button1_Click"

protected void Button1_Click(object sender, EventArgs e)
{
    ((Button)sender).Enabled = false;
}

Lastly, keep in mind that preventing duplicate button presses doesn't prevent two different users from submitting the same data at the same time. Make sure to account for that on the server side.

Can the down-voters please let me know what's wrong? If I'm wrong, I would like to know so I can remove this answer and learn from my mistakes. Or if you just don't understand my code or the reasoning behind it, please ask. In the latter case, you're doing a disservice to the community by down-voting good advice.

c# - OnclientClick and OnClick is not working at the same time? - Stac...

c# asp.net postback onclick onclientclick
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Your problem is that your hidden field is outside the update panel. Even though an update panel has access to all controls on a page during postback (since it acts like a normal postback), it does NOT update any controls on the page client-side that are outside of the ContentTemplate. So your code in the codebehind that is changing the value of the hidden field is not having an effect on the value on the client side. That's why the second time you click the button it is still set to true.

You will need to either a) put the hidden field inside the UpdatePanel (or you could put it in its own panel with UpdateMode set to Always); or b) have some javascript on client-side that fires when the UpdatePanel call completes that sets the value back to false.

you're a gentleman and a scholar. I did move it inside the Update panel before but it didn't recognise the hidden field so I gave up on that approach. This time I put it inside the <ContentTemplate> and it worked.

2 years later and this is still right on the money!! Thank you sir

This helped me with a slightly different problem with saving a value in the hidden field. Thank you.

javascript - asp.net hidden field not retaining value when updated fro...

javascript asp.net hidden-field
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Your problem is that your hidden field is outside the update panel. Even though an update panel has access to all controls on a page during postback (since it acts like a normal postback), it does NOT update any controls on the page client-side that are outside of the ContentTemplate. So your code in the codebehind that is changing the value of the hidden field is not having an effect on the value on the client side. That's why the second time you click the button it is still set to true.

You will need to either a) put the hidden field inside the UpdatePanel (or you could put it in its own panel with UpdateMode set to Always); or b) have some javascript on client-side that fires when the UpdatePanel call completes that sets the value back to false.

you're a gentleman and a scholar. I did move it inside the Update panel before but it didn't recognise the hidden field so I gave up on that approach. This time I put it inside the <ContentTemplate> and it worked.

2 years later and this is still right on the money!! Thank you sir

This helped me with a slightly different problem with saving a value in the hidden field. Thank you.

javascript - asp.net hidden field not retaining value when updated fro...

javascript asp.net hidden-field
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It looks like when the button is disabled .Net doesn't bother adding the necessary bits to handle the cross page postback on the client, so they will be missing when the button is enable client-side.

I guess one solution would be to have the button enabled to start with (so that .Net adds the cross page postback controls) and then disable it using javascript as soon as the control loads on the client. But this sounds a bit clunky.

asp.net - Cross Page Postback doesn't work for client-side enabled but...

asp.net postback
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You can use the OnClientClick attribute for the asp button and add return false; which prevents the postback:

<asp:Button ID="1Btn" runat="server" Text="1" Height="70px" Width="70px" 
    OnClientClick="btn1Click(); return false;" />

c# - How to make ASP.NET button call client side javascript and not do...

c# javascript asp.net .net
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Once the page has begun the postback, the client will not receive any data from the server until the server code is complete. Your commands to OffDivOn() and OffDivOff() are not getting sent to the client. Your options are:

  • Begin showing your loading image before the submit happens using javascript. Try wiring to the onclick handler of your submit button or handing the onsubmit event of your form and call OffDivOn().

asp.net - is it possible to show an ovelay div with loading image insi...

asp.net ajax postback overlay modal-dialog
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If you simply disable the button then ASP.NET won't post the form. Also you want to deal with client-side validation. Here's my solution:

<asp:Button runat="server" ID="btnSave" 
   Text="Save" OnClick="btnSave_Click" 
   OnClientClick="if (!Page_ClientValidate()){ return false; } this.disabled = true; this.value = 'Saving...';" 
   UseSubmitBehavior="false" />

See @Dave Ward's post for a description of UseSubmitBehavior.

If you have multiple validation groups you'll need to enhance this solution for that.

Thanks a lot, this adjustment from another post (I can't find it now) worked for me : OnClientClick=" if (Page_IsValid) {this.value='Saving...';this.disabled=true; }"

Removing this part if (!Page_ClientValidate()){ return false; } fixed your solution for me. .net 4.5.2 default webform app.

Technically you only need the 'this.disabled=true;'. Everything else is optional

Not working if use javascript function in OnClientClick ?

asp.net - How do I prevent users clicking a button twice? - Stack Over...

asp.net webforms
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What if the button did an Ajax request back to the original page and got the hidden field values. You could then construct another form on the page with the hidden fields using javascript and submit it -- with the download option. Since the request will return an application/ms-excel file, it shouldn't refresh the current page but the download should still occur. You'd need to make sure that the button click didn't cause a postback by returning false from the client-side function. Note that this only works if the post of the generated form results in a download, not a new html page.

<script type="text/javascript">
   function submitReport( button ) {
      PageMethod.SubmitReport(onSuccess,onFailure,{ control: button });
   }

   function onSuccess(values,ctx) {
      var form = document.createElement('form');
      form.action = reporting-services.url;
      form.method = 'post';
      document.body.appendChild(form);
      .... add hidden fields to form from returned values
      form.submit();
      document.body.removeChild(form);
   }

   function onFailure(error,ctx) {
      ... pop up some error message....
   }

  </script>

  ...

  <asp:Button runat="server" id="reportButton" ClientClick="submitReport(this);return false;" Text="Report" />

asp.net - Close Browser Window after Form Post - Stack Overflow

asp.net javascript html reporting-services
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I believe adding "return false;" to your OnClientClick expression will solve your problem. This will prevent the button from making a postback but will still execute your client side javascript function.

<asp:Button ID="btn1" UseSubmitBehavior="false" OnClientClick='moveComment(txtComment_<%# Eval("Container.DataItemIndex") %>); return false;' runat="server" Text="add comment"/>

asp.net - OnClientClick and Calling Custom JavaScript Function - Stack...

asp.net
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asp.net web forms will always do a postback on a runat="server" button click. that is how it reaches the code behind (.cs file). for client side clicks you can either use aspx ajax or jQuery click or javascript onclick functions to prevent postbacks. For this very reason more and more asp.net developers are moving to asp.net mvc.

Try just creating a simple html button and doing and onclick to run you javascript function:

<button onclick="javascript:some_js_function();">Click Me</button>
<button id="btn">Click Me</button>

in you document.ready:

$('form').on('click', '#btn', function(evt) {
    evt.preventDefault();
    some_js_function();
});

javascript - How to stop the page refresh after click on button in asp...

javascript asp.net html5 c#-4.0
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It seems like there is some sort of confussion here that I would like to help solve. Server code and client code are separated. When client code executes (such as javascript) the server has no way to know what happened so your server side code (code behind) is not aware of any changes. In order to have the javascript variable information on the code behind you'll need to send that variable value back to the server and one of the mechanisms is the one provided by user2952502. I think in your case a postBack (using a submit or link button) would be more appropiate, right? I think you're trying to redraw the page based on something that the user did (since you're using javascript).

I think we should have some more information to understand the whole scope of your question and probably suggest you a better way to deal with it.

jquery - how to pass javascript variable to embedded Server Side code ...

javascript jquery asp.net webforms
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The onclick event of an asp:button object will call the client validation if you set it up with a validtion control. If you have not set up the onclick event to the button it is not going to know what method to call. If you have set up the onclick then the javascript call is not needed. If you set up a validation control to use the validation script and the client side validation .net will handle the postback call. And looking at your script you may be better served using a required field validator than your custom script.

Thanks for your reply. Can you help me in getting the desired results?

The required field validator control has the functionality you want built in. you just need to add a RequiredFieldValidator for each of your textboxes that you want to require. If this is dynamic on page load you can add one for each and enable/disable them in your page load/databind event. Asp.net buttons by default cause validation.

javascript - Execute Server Side from Client Side - Stack Overflow

javascript asp.net
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You are doing a postback with every key press. When the page reloads, it will not retain focus where you would expect. I recommend implementing this in JavaScript on the client, or using a search button instead of TextChanged event.

You misread something, this is not a web application, it's desktop one. Also, as I said, I would like searching to be automatic - without pressing any search button.

c# - Search listview items using textbox - Stack Overflow

c# listview search
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The ASP.NET Button has an OnClick property that allows to set the server-side event handler. It also has an OnClientClick property which can contain some client code to execute first when the button is clicked. If that client code returns false, the postback to the server is canceled.

Both properties can be set in markup for your buttons:

<asp:TextBox ID="txtPIN" runat="server" />
<asp:Button runat="server" Text="0" OnClientClick="return addDigit(this);" OnClick="btn_Click" />
<asp:Button runat="server" Text="1" OnClientClick="return addDigit(this);" OnClick="btn_Click" />
<asp:Button runat="server" Text="2" OnClientClick="return addDigit(this);" OnClick="btn_Click" />
...

The Javascript addDigit function should return false if less than 5 digits have been inserted in the TextBox:

<script type="text/javascript">
    function addDigit(btn) {
        var txtPIN = document.getElementById('<%= txtPIN.ClientID %>');
        txtPIN.value += btn.value;
        return txtPIN.value.length >= 5;
    }
</script>

That script block can be in the <Head> section of the HTML document or at the bottom of the form.

The event handler in code-behind would perform the PIN validation:

protected void btn_Click(object sender, EventArgs e)
{
    // Check database to validate the PIN
    string pin = txtPIN.Text;
    ...
}

Note: The syntax '<%= txtPIN.ClientID %>' is used in the Javascript code to account for the possible ID mangling performed by ASP.NET.

false
<asp:Button ID="btnBack" runat="server" Text="Back" OnClientClick="removeLastDigit(); return false;" />

Using the following function added to the Javascript block:

function removeLastDigit() {
    var txtPIN = document.getElementById('<%= txtPIN.ClientID %>');
    txtPIN.value = txtPIN.value.substring(0, txtPIN.value.length - 1);
}

This was perfect to get me on the right track! Thanks so much! I wasn't sure where to put the script so I added a line to your answer. Probably obvious to most... but for the benefit of the newbies like me. :)

In fact, the script block is often put at the bottom of the form (see stackoverflow.com/questions/2451417/). In your case, it should work in both places. The advantage of putting it at the bottom is that some code involving the HTML elements can be executed immediatly, which does not work if the code is in the head section (because the elements are not loaded yet).

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asp.net - How to use client side script on button click to modify text...

asp.net web-applications webforms visual-studio-2005 client-side
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This is how validation works, if you can post back the page without some client side validators firing then the button or link or whatever fires the postback is either not in the validation group of the validators that are not firing or it has CausesValidation set to false.

c# - CustomValidator with server side validation only - Stack Overflow

c# asp.net
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PostBack is the name given to the process of submitting an ASP.NET page to the server for processing. PostBack is done if certain credentials of the page are to be checked against a database (such as verification of username and password) or doing some calculation. This is something that a client machine is not able to accomplish and thus these details have to be posted back to the server.Postback occurs usually when you click a button, radiobutton, checkbox or any other control(if you specify OnClick event in the markup). Many other event also call postback if specified in the markup.

Note: When a postback goes to server it also process page_Load event of the current page.

web - What is a postpback request in asp.net? - Stack Overflow

asp.net web request
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I'd go for the simplest thing - and the issue is not making the button invisible, but having an invisible button, that one can click on from javascript, and having the button call it's event handler. I have the same hack as the OP: make the button permanently invisible by setting it's style=display:none;. In that way the button exists on the client page, my JS clicks it, and then the buttons eventhandler on the server gets called on postback. This didnt work properly in Firefox until I set UseSubmitBehavior=False. Now it works in IE and FF.

thanks for the response. I already tried adding UseSubmitBehavior=False but I still didn't have any luck with it. I also tried removing Visible="false" and added style="display:none" but still the event doesn't fire up. :(

first remove all display or visible false attribute and try is that works?

yes. I tried removing all the visible false attributes. after adding items on my gridview and clicking the button, the gridview refreshes. it works that way. but i need it to refresh without clicking the button. thanks for helping.

but my problem is I can't use btnRefresh.UniqueID since my javascript is in an external file. i believe i also tried __dopostback(btn) without luck.

javascript - asp:Button Click Event doesn't fire - Stack Overflow

javascript asp.net button onclick
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You need to be careful that the postback occurs before you disable the button through client script. This is a common gotcha with ajax and input boxes. Disabling an input box prevents the data from being sent from the browser, even if you can see text within it while it is disabled. The answer is that you need to use jquery for this to ensure the server-side code runs first before it is disabled.

I did it..I ran this code but the code behind never executed $('input[type=submit]').click(function() { this.disabled = true; });

asp.net - Disable a button on click - Stack Overflow

asp.net javascript jquery
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The checked change of your radiobutton fires a postback, but the required field validator will do a validation in the client side , which is blocking you. So you should disable the required filed validator in the client side. Write a client side onCheckedChange event for that radio button , and then in that event, Enable or disable the requiredfield validator in the client side using javascript. you can use the below javascript functionality

ValidatorEnable(getElelementById('#<%=rfvNAVEStimate.ClientID %>') ,fale); // this will disable the validator

if you pass true . it will enable the validator

Correct me if m wrong, but I dont think we can write a client side event for an asp radio button. And there are few other things that happen on click as well in my code behind. Is there no other way to do this on server side..

You can bind a client side event for the radio button using jQuery. So your client side evnt will fire first and then it will go for the server side event.

If your required field validator is there, it will prevent any postback. Then I think, better you remove that required field validator, and just do the validation in code. Or One more thing, you can do is, instead of the required field validator, use asp.net custom validator. So for that custom validator you can write a client side or server side function, and in that function check if the radio button is checked or not and do the validation based on that.

c# - Required Field validator Not working from OnCheckedChanged Event ...

c# asp.net code-behind requiredfieldvalidator