How can I set up JavaScript validation to display an error message when certain fields are incorrect upon clicking a button? Although I would like to achieve this with JavaScript (or perhaps at a later date), I am uncertain of the necessary steps to take. Currently, the onclick function on the server side fails to run when the button is clicked. Any insights or suggestions would be greatly appreciated.
One convenient option is to utilize <asp:Validator elements, which offer a variety of validation types including required field validators and regex validators.
These validators handle data validation on both the client side and server side automatically (unless you opt out of client side checking).
Using these built-in validators is far simpler than manually coding validation logic in JavaScript and server-side scripts.
Specifically, when incorporating an onclick event handler for a submit button, the boolean return value dictates whether the form should be submitted. By returning false if the data is invalid, you can prevent form submission.
<asp:Button Text="Submit" OnClientClick="return Validate();" />
<script type="text/Javascript">
function Validate()
{
if(requiredFieldAIsMissing) return false;
return true;
}
</script>
Consider this alternative:
<asp:Button ID="myButton" Text="Press Here!" OnClick="myButton_OnClick" OnClientClick="javascript:confirm('Are you sure?')" />
The OnClientClick attribute generates the necessary javascript (before the code needed for postback handling). When you return false from this event, it stops the remaining part of the event and prevents the postback from occurring.
To gain a better grasp of this concept, consider the following example.
HTML:
<asp:textbox id="myText" runat="server" text="Hello" />
<asp:button id="myButton" runat="server" text="Click Me" OnClick="Server_Event" />
ON Page_Load:
//Include onclick function with return statement here
myButton.Attributes.Add("onclick","return ButtonClicked()");
Javascript:
function ButtonClicked(){
var txt = document.getElementById("myText");
if(txt.value != "Hello"){
alert("It is not Hello, I am NOT posting back!");
return false;
} else {
alert("It is Hello, I am posting back!");
return true;
}
}
My web application serves as a monitoring interface for tracking changes in "objects" processed by the computer, specifically when they exceed a certain threshold. The Node Js server is running on the same machine and is responsible for displaying data in ...
Currently, I am facing an issue with loading and playing videos via streaming in my Android app using a JavaScript code inside an HTML file. My approach involves using a WebView to showcase the video content. However, the challenge lies in the fact that th ...
Is there a method to troubleshoot code that has been added through the firefox developer console terminal? For example, I added document.onkeydown = function(event) { // code logic for checking keys pressed } If only I could determine which .js file t ...
I encountered a MultiValueDictKeyError while working in Django. The issue arises when trying to logout a user from my website using the following code: In HTML </li> <li class="nav-item mr-3"> ...
Hello, this marks my debut on stack overflow with a question. I've created a game inspired by old school RPGs where players choose from three heroes based on the Marvel universe to battle one of three enemies. The problem I'm facing is that even ...
I'm facing a unique issue with Angular where my select list has an empty first option. What's interesting is that when the select tag is placed outside of ng-repeat, there is no blank default value. However, when using the ng-option attribute wit ...
Looking to improve my JavaScript logic skills as a beginner. Appreciate any tips or feedback on the function and not just this specific question. I'm curious why the code outputs --> [3,5] function divisors(integer) { let divisors = [] for (le ...
Although I found this solution, it seems to be quite slow. I am looking for the quickest way to traverse directories without using npm packages. Any suggestions? ...
As I was going through the documentation for the bindonce directive, a question popped into my head regarding the distinction between bo-html and bo-text. bo-html: This evaluates "markup" and displays it as HTML within the element. bo-text: ...
This particular issue is in reference to the jsfiddle link provided below: http://jsfiddle.net/n1cf938h/ Within the fiddle, there is an ng-repeat function generating a list of dates. My question pertains to identifying which dropdown option the user has s ...
Looking for advice on setting up a sleek email signup bar that remains at the top of the browser while users scroll and navigate through different pages. I am working with WordPress and have jquery already loaded, but have not yet worked with either. Up ...
Within a PHP project I am working on, I have encountered a need to organize a specific column using a custom condition or order rather than relying on the default ordering provided by DataTable (ascending or descending). The project involves four distinct ...
I'm diving into the world of morph targets and three.js, but I'm struggling to find comprehensive documentation on this topic. Upon reviewing the source code, it seems like morphTargetInfluences[] is the key element. Can someone explain how thi ...
I'm encountering an ES Lint Parsing Error in my Vue page due to a syntax issue. The problem seems to be arising from a parameter in my method that contains a dot symbol. Error - Syntax Error: Unexpected token (1:1628) <div class="text-sm ...
When using Restangular, default behavior for PUT/PATCH/POST operations is to use the id of an item as the primary key. But what if you want to use a custom key like a slug or number instead? // GET to /users Users.getList().then(function(users) { var ...
I am currently delving into Angular JS in order to fulfill some academic requirements. The issue I am facing is with the rendering of a landing page after successfully logging in through a login portal that caters to three types of users. Strange enough, w ...
Hi there, I am faced with the challenge of reading form elements sent from a curl library on another server using C#. Being primarily a PHP developer, I am unsure of how to access these variables in C#. If I were coding this in PHP, my code would look some ...
Having some trouble with a concept in ASP.Net that's causing me quite the headache. I am fairly new to ASP.Net and struggling with something that seems much easier in PHP. I created an img element with an empty src attribute : <img runat="server" ...
I have implemented a script on my page that handles form submissions for multiple forms by calling a specific action. Here is the script: $(function () { $('form').submit(function () { if ($(this).valid()) { $.ajax({ ...
I am facing a challenge that I can't find any solutions for online or elsewhere. The task at hand seems straightforward. I am using the Chrome console and attempting to run Javascript code to navigate between pages with pauses in between. It feels lik ...