Validation
Vue Bootstrap 5 Validation
Provide valuable, actionable feedback to your users with Vue form validation, via browser default behaviors or custom styles and JavaScript.
Note: We currently recommend using custom validation styles, as native browser default validation messages are not consistently exposed to assistive technologies in all browsers (most notably, Chrome on desktop and mobile).
Basic example
For custom MDB 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.
How it works
Note: Our validation can be used together with packages specializing in form validation. Check out this tutorial to see how to painlessly integrate MDB Vue with VeeValidate.
Here’s how form validation works with MDB:
-
HTML form validation is applied via CSS’s two pseudo-classes,
:invalid
and:valid
. It applies to<MDBInput>
and<MDBTextarea>
elements. -
MDB 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,
isValid
andisValidated
properties may be used on validated components 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
validFeedback
andinvalidFeedback
properties for validated components.
With that in mind, consider the following demos for our custom form validation styles, optional server-side classes, and browser defaults.
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.
While these feedback styles cannot be styled with CSS, you can still customize the feedback text through JavaScript.
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
isValid
and isValidated
properties. Note that
invalidFeedback
and validFeedback
are also supported with these
properties.
Supported elements
Validation styles are available for the following form controls and components:
MDBInput
MDBTextarea
MDBCheckbox
MDBRadio
MDBSelect
MDBAutocomplete
Tooltips
If your form layout allows it, you can add
tooltipFeedback
property for validFeedback
,
invalidFeedback
properties 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.
Validation on event
Use validationEvent="event name"
property for input and textarea or
validateOnChange
property for checkbox and radio inputs to validate elements on
specific event instead of submit.
Adding validation attributes to input element such as
minLength
or pattern
will show validation message based on your
default browser validation response for invalid element. Add proper information about
validation requirements in title
attribute for better accessibility.
Customizing
Validation states can be customized via Sass with the
$form-validation-states
map. Located in our _variables.scss
file,
this Sass map is looped over to generate the default valid
/invalid
validation states. Included is a nested map for customizing each state’s color. While no other
states are supported by browsers, those using custom styles can easily add more complex form
feedback.
Please note that we do not recommend customizing these values without also modifying the
form-validation-state
mixin.
This is the Sass map from _variables.scss
. Override this and recompile your Sass
to generate different states:
This is the loop from forms/_validation.scss
. Any modifications to the above Sass
map will be reflected in your compiled CSS via this loop: