How can I show an ASP label using JavaScript?

In order to display my label when a user leaves out a field before clicking the button, I have set up this code. However, nothing happens when I click the button. What am I missing?

<asp:Label ID="lblError" runat="server" 
Text="* Please complete all mandatory fields" style="display: none;" >
</asp:Label>

When the button is clicked, this function is called:

function valSubmit(){
    varName = document.form1.txtName.value;
    varSurname = document.form1.txtSurname.value;

    if (varName == "" || varSurname == "") 
    {
     document.getElementById('lblError').style.display = 'inherit'; 

    }
    else
    { 

     .................other code goes here...........................
    return true; 
    } 

}

Answer №1

Have you considered using Validation controls? These controls provide both client and server side validation without much effort on your part - not that I'm looking for shortcuts or anything... ;-)

Adding a comment:

The RequiredFieldValidator can be configured to show a single red asterisk next to each control, and while a validation summary control is an option, it does take up space.

It's possible that ASP.Net may be altering the control names, so make sure your JavaScript code reflects this:

document.getElementById('<%= lblError.ClientID %>').style.display = 'inherit';

You should give that a try...

Personally, I still recommend using the Validator controls ;-)

Answer №2

A better practice would be to avoid using lblError as an ID in JavaScript code. It is recommended to use the following instead:

'<%= lblError.ClientID %>'

This approach is only applicable if you are generating the JavaScript code within an ASP.NET file.

Answer №3

for your upcoming occasion, consider using this method:

document.getElementById('<%= lblError.ClientID %>').style.display = ""; or
document.getElementById('<%= lblError.ClientID %>').style.display = "block"

Alternatively, you can handle it server-side. Start by making it invisible on form load event with lblEror.visible = false and removing style ="display:none" from the HTML. Then, show it when needed and hide it again after processing.

If you prefer a JavaScript approach, try this workaround: remove style attribute from the ASP label. Disable it in a JS function on body onload. Upon button click event, use a method like this to make it visible:

    function Validate()
    {
         var objLbl = $get('<%=lblError.ClientID%>');
         if (validations fail)
         {
             objLbl.style.display = ""; //displays label
             return false;
         }
         else
         {
             objLbl.style.display="none" //hides label
             return true;
         }
    }
<asp:button id="btnValidate" runat="server" onclientclick="return validate();"/>

Give it a try and hopefully, it will solve your issue.

Answer №4

Consider using jQuery for selecting elements based on classes rather than ids, as classes are more versatile and less likely to be changed when the page is rendered.

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Doesn't seem like jQuery's .blur() is responsive on dynamically created fields

I am currently designing a login form that includes a registration form as well. Using jQuery, the email field is generated dynamically. The labels are positioned below the fields so that they can be placed inside the field. As the field gains focus or ha ...

Using HTML to design interactive buttons that can send API requests and display their current status

Seeking assistance with creating buttons to control a remote light's ON and OFF states while reflecting their status as well. The specific http API calls for the light are necessary to toggle its state. Turn On = http://192.168.102.22:3480/data_requ ...

PayPal users have the option to adjust the price of their purchase prior to final

Currently facing a minor issue with my website. I am trying to allow users to customize certain options before checking out, which would impact the final price. While I have successfully implemented this feature, users can easily inspect element and modify ...

Difficulty in comparing passwords using bcrypt encryption method

As a beginner in express js, I have successfully implemented the register functionality in my app. However, I am facing an issue with the login process. I am trying to compare the password stored in the database with the one provided by the user using bcry ...

Activate the mouseenter event as soon as an animated element makes contact with the cursor

As I venture into the world of web development, I am currently working on creating a game where the main objective is to avoid touching moving circles with the cursor. My approach involved using a mouseenter event as shown in the JSFiddle example below: $ ...

Tips for setting a date format to dd-mm-yyyy in Internet Explorer to match the one displayed in Google Chrome

Since type=date does not work in IE, is there a way to achieve the dd-mm-yyyy format like in other browsers? Any suggestions would be greatly appreciated. Thanks! ...

Single jQuery scrolling loader malfunctioning in WebKit browser

I've been conducting an interesting experiment in which new entries are dynamically loaded onto a page as you scroll down. Check out a practical demonstration here. In Firefox, everything seems to be working perfectly. However, when viewed in WebKit ...

"Running 'npm run build' in Vuejs seems to have a mind of its own, acting

Recently, I completed a project and uploaded it to Github. The issue arises when I attempt to clone it to my live server - only about 1 out of 10 times does everything function correctly after running npm run build. My setup consists of Ubuntu 16 with ngin ...

Using Angular to display the initially selected option value in a select dropdown menu

Struggling to set the default selected option in a select input using Angular. I've tried several solutions with no success. It's baffling why this is proving so difficult for me. Any assistance would be greatly appreciated, thank you. The selec ...

Dynamically attach rows to a table in Angular by triggering a TypeScript method with a button click

I need help creating a button that will add rows to a table dynamically when pressed. However, I am encountering an error when trying to call the function in TypeScript (save_row()). How can I successfully call the function in TypeScript and dynamically a ...

Sort ng-repeat based on the initial character

Working in AngularJS, I am handling an array of objects and aiming to display filtered data based on the first letter. My initial method used was as follows. HTML: <p ng-repeat="film in filmList | startsWith:'C':'title'">{{film. ...

Update the text content in the specific span element when the class attribute matches the selected option in the

How can I dynamically update text inside a span based on matching classes and attributes without hardcoding them all? An ideal solution would involve a JavaScript function that searches for matches between span classes and select field options, updating t ...

Creating a flexible route path with additional query parameters

I am facing a challenge in creating a unique URL, similar to this format: http://localhost:3000/boarding-school/delhi-ncr However, when using router.push(), the dynamic URL is being duplicated like so: http://localhost:3000/boarding-school/boarding-school ...

Issue with height in self-invoking function not functioning correctly

Issue with height not functioning correctly inside self-invoking function, but works fine within (document).ready(function() (function($){ var clientHeight = document.getElementById('home').clientHeight; alert(clientHeight); })(jQuery); <di ...

Nest JS Guards - Employ either of two approaches

I have implemented two different JWT based strategies in my application: The first strategy involves single sign-on for organization members, where an external provider generates a JWT. The second strategy is for email/password authenticated external user ...

How can we show pictures when a user clicks?

After creating a model for displaying images in a modal when clicked by the user, I encountered an issue. Whenever I try to access the images from the gallery within the modal content, it only displays a blank popup. I want the pictures from the image gall ...

How do I send a jQuery table object to a web worker using Javascript?

I have an HTML table with various columns and rows that can be edited by users directly. Whenever a user makes changes to the table, I need to calculate certain sums on the rows of the table. Initially, the function responsible for calculating these sums ...

Using AngularJS Typeahead with restrictions on $http requests

I have been attempting to restrict the number of results displayed by Angular Bootstrap Typeahead during Async calls, but unfortunately, it does not seem to be functioning as expected. <input type="text" ng-model="asyncSelected" placeholder="Locations ...

What could be the reason for a variable not being assigned a value following the xmlhttp.responseText?

During the validation process of a send-fax form, I am checking if a fax has been previously sent using our software fax package. This involves a simple query to a table executed by a script, which will return text if a previous fax exists or blank if not. ...

Using PHP and Ajax to retrieve a distinct string prior to executing a time-consuming script

It's a question that comes up often. In short, I want to display progress to the user while a lengthy script is running. This is my approach: store "progress" in mysql so that Ajax can access it (via PHP). "progress()" is the lengthy script being te ...