Bootstrap 5 Tutorial In Hindi #31 | Form Validation.

Hello Dear Readers, Today In this Post, You will learn Bootstrap 5 Tutorial In Hindi #31 | Form Validation. Earlier I have shared the Bootstrap 5 Tutorial In Hindi #30 | Inline & Horizontal Form. and now it’s time to Bootstrap 5 Form Validation.


In this tutorial, You will learn full Bootstrap 5. If you want to go deep into the tutorial so you can watch the full video which is below Hope it will help you all thank you for visiting.


In this tutorial, you will learn Bootstrap Tutorial In Hindi, Bootstrap 5 Form Validation. Here You can learn what is a bootstrap framework, what are the advantages of the bootstrap tutorial in Hindi. Make sure to Subscribe, Share the video, and Like it, for more tutorials in Hindi like this one!



Provide valuable, actionable feedback to your users with HTML5 form validation, via browser default behaviors or custom styles and JavaScript.


How it works

Here’s how form validation works with Bootstrap:


  • HTML form validation is applied via CSS’s two pseudo-classes, :invalid and :valid. It applies to <input><select>, and <textarea> elements.
  • Bootstrap scopes the :invalid and :valid styles to parent .was-validated class, usually applied to the <form>. Otherwise, any required field without a value shows up as invalid on page load. This way, you may choose when to activate them (typically after form submission is attempted).
  • To reset the appearance of the form (for instance, in the case of dynamic form submissions using AJAX), remove the .was-validated class from the <form> again after submission.
  • As a fallback, .is-invalid and .is-valid classes may be used instead of the pseudo-classes for server-side validation. They do not require a .was-validated parent class.
  • Due to constraints in how CSS works, we cannot (at present) apply styles to a <label> that comes before a form control in the DOM without the help of custom JavaScript.
  • All modern browsers support the constraint validation API, a series of JavaScript methods for validating form controls.
  • Feedback messages may utilize the browser defaults (different for each browser, and unstylable via CSS) or our custom feedback styles with additional HTML and CSS.
  • You may provide custom validity messages with setCustomValidity in JavaScript.

With that in mind, consider the following demos for our custom form validation styles, optional server-side classes, and browser defaults.

Play Video

Custom styles

For custom Bootstrap form validation messages, you’ll need to add the novalidate boolean attribute to your <form>. This disables the browser default feedback tooltips, but still provides access to the form validation APIs in JavaScript. Try to submit the form below; our JavaScript will intercept the submit button and relay feedback to you. When attempting to submit, you’ll see the :invalid and :valid styles applied to your form controls.


Custom feedback styles apply custom colors, borders, focus styles, and background icons to better communicate feedback. Background icons for <select>s are only available with .form-select, and not .form-control.


Browser defaults

Not interested in custom validation feedback messages or writing JavaScript to change form behaviors? All good, you can use the browser defaults. Try submitting the form below. Depending on your browser and OS, you’ll see a slightly different style of feedback.  


Server side

We recommend using client-side validation, but in case you require server-side validation, you can indicate invalid and valid form fields with .is-invalid and .is-valid. Note that .invalid-feedback is also supported with these classes.


For invalid fields, ensure that the invalid feedback/error message is associated with the relevant form field using aria-describedby (noting that this attribute allows more than one id to be referenced, in case the field already points to additional form text).

To fix issues with border radii, input groups require an additional .has-validation class.



If your form layout allows it, you can swap the .{valid|invalid}-feedback classes for .{valid|invalid}-tooltip classes to display validation feedback in a styled tooltip. Be sure to have a parent with position: relative on it for tooltip positioning. In the example below, our column classes have this already, but your project may require an alternative setup.

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