React Form Validation

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

Example#

For custom CoreUI form validation messages, you'll need to add the noValidate boolean property to your <CForm>. 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.

const [validated, setValidated] = useState(false)
const handleSubmit = (event) => {
  const form = event.currentTarget
  if (form.checkValidity() === false) {
    event.preventDefault()
    event.stopPropagation()
  }
  setValidated(true)
}
return (
  <CForm
    className="row g-3 needs-validation"
    noValidate
    validated={validated}
    onSubmit={handleSubmit}
  >
    <CCol md={4}>
      <CFormInput
        type="text"
        defaultValue="Mark"
        feedbackValid="Looks good!"
        id="validationCustom01"
        label="First name"
        required
      />
    </CCol>
    <CCol md={4}>
      <CFormInput
        type="text"
        defaultValue="Otto"
        feedbackValid="Looks good!"
        id="validationCustom02"
        label="First name"
        required
      />
    </CCol>
    <CCol md={4}>
      <CFormLabel htmlFor="validationCustomUsername">Username</CFormLabel>
      <CInputGroup className="has-validation">
        <CInputGroupText>@</CInputGroupText>
        <CFormInput
          type="text"
          aria-describedby="inputGroupPrependFeedback"
          feedbackValid="Please choose a username."
          id="validationCustomUsername"
          required
        />
      </CInputGroup>
    </CCol>
    <CCol md={6}>
      <CFormInput
        type="text"
        aria-describedby="validationCustom03Feedback"
        feedbackInvalid="Please provide a valid city."
        id="validationCustom03"
        label="City"
        required
      />
    </CCol>
    <CCol md={3}>
      <CFormSelect
        aria-describedby="validationCustom04Feedback"
        feedbackInvalid="Please select a valid state."
        id="validationCustom04"
        label="State"
        required
      >
        <option disabled>Choose...</option>
        <option>...</option>
      </CFormSelect>
    </CCol>
    <CCol md={3}>
      <CFormInput
        type="text"
        aria-describedby="validationCustom05Feedback"
        feedbackInvalid="Please provide a valid zip."
        id="validationCustom05"
        label="Zip"
        required
      />
    </CCol>
    <CCol xs={12}>
      <CFormCheck
        type="checkbox"
        id="invalidCheck"
        label="Agree to terms and conditions"
        required
      />
      <CFormFeedback invalid>You must agree before submitting.</CFormFeedback>
    </CCol>
    <CCol xs={12}>
      <CButton color="primary" type="submit">
        Submit form
      </CButton>
    </CCol>
  </CForm>
)

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.

<CForm className="row g-3">
  <CCol md={4}>
    <CFormInput
      type="text"
      id="validationDefault01"
      label="First name"
      defaultValue="Mark"
      required
    />
  </CCol>
  <CCol md={4}>
    <CFormInput
      type="text"
      id="validationDefault02"
      label="Last name"
      defaultValue="Otto"
      required
    />
  </CCol>
  <CCol md={4}>
    <CFormLabel htmlFor="validationDefaultUsername">Username</CFormLabel>
    <CInputGroup>
      <CInputGroupText id="inputGroupPrepend02">@</CInputGroupText>
      <CFormInput
        type="text"
        id="validationDefaultUsername"
        defaultValue=""
        aria-describedby="inputGroupPrepend02"
        required
      />
    </CInputGroup>
  </CCol>
  <CCol md={6}>
    <CFormInput type="text" id="validationDefault03" label="City" required />
  </CCol>
  <CCol md={3}>
    <CFormSelect id="validationDefault04" label="State">
      <option disabled>Choose...</option>
      <option>...</option>
    </CFormSelect>
  </CCol>
  <CCol md={3}>
    <CFormInput type="text" id="validationDefault05" label="Zip" required />
  </CCol>
  <CCol xs={12}>
    <CFormCheck type="checkbox" id="invalidCheck" label="Agree to terms and conditions" required />
  </CCol>
  <CCol xs={12}>
    <CButton color="primary" type="submit">
      Submit form
    </CButton>
  </CCol>
</CForm>

Custom validation#

In case you require custom or server-side validation, you can indicate invalid and valid form fields with invalid and valid boolean properties.

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).

<CForm className="row g-3">
  <CCol md={4}>
    <CFormInput
      type="text"
      id="validationServer01"
      label="Email"
      feedback="Looks good!"
      defaultValue="[email protected]"
      valid
      required
    />
  </CCol>
  <CCol md={4}>
    <CFormInput
      type="text"
      id="validationServer02"
      label="Repeat email"
      feedback="Looks good!"
      defaultValue="[email protected]"
      valid
      required
    />
  </CCol>
  <CCol md={4}>
    <CFormLabel htmlFor="validationServerUsername">Username</CFormLabel>
    <CInputGroup className="has-validation">
      <CInputGroupText id="inputGroupPrepend03">@</CInputGroupText>
      <CFormInput
        type="text"
        id="validationServerUsername"
        feedback="Please choose a username."
        defaultValue=""
        aria-describedby="inputGroupPrepend03"
        invalid
        required
      />
    </CInputGroup>
  </CCol>
  <CCol md={6}>
    <CFormInput
      type="text"
      id="validationServer03"
      label="City"
      feedback="Please provide a valid city."
      invalid
      required
    />
  </CCol>
  <CCol md={3}>
    <CFormSelect
      id="validationServer04"
      label="State"
      feedback="Please provide a valid city."
      invalid
    >
      <option disabled>Choose...</option>
      <option>...</option>
    </CFormSelect>
  </CCol>
  <CCol md={3}>
    <CFormInput
      type="text"
      id="validationServer05"
      label="zip"
      feedback="Please provide a valid zip."
      invalid
      required
    />
  </CCol>
  <CCol xs={12}>
    <CFormCheck
      type="checkbox"
      id="invalidCheck"
      label="Agree to terms and conditions"
      invalid
      required
    />
    <CFormFeedback invalid>You must agree before submitting.</CFormFeedback>
  </CCol>
  <CCol xs={12}>
    <CButton color="primary" type="submit">
      Submit form
    </CButton>
  </CCol>
</CForm>

Supported elements#

Validation styles are available for the following form controls and components:

<CFormCheck>s
<CFormInput>s
<CFormSelect>s
<CFormTextarea>s

<CForm validated={true}>
  <div className="mb-3">
    <CFormTextarea
      feedbackInvalid="Please enter a message in the textarea."
      id="validationTextarea"
      label="Textarea"
      placeholder="Required example textarea"
      required
    ></CFormTextarea>
  </div>
  <CFormCheck
    className="mb-3"
    id="validationFormCheck1"
    label="Check this checkbox"
    feedbackInvalid="Example invalid feedback text"
    required
  />
  <CFormCheck
    type="radio"
    name="radio-stacked"
    id="validationFormCheck2"
    label="Check this checkbox"
    required
  />
  <CFormCheck
    className="mb-3"
    type="radio"
    name="radio-stacked"
    id="validationFormCheck3"
    label="Or toggle this other radio"
    feedbackInvalid="More example invalid feedback text"
    required
  />
  <div className="mb-3">
    <CFormSelect
      feedbackInvalid="Example invalid select feedback"
      aria-label="select example"
      required
    >
      <option selected="" value="">
        Open this select menu
      </option>
      <option value="1">One</option>
      <option value="2">Two</option>
      <option value="3">Three</option>
    </CFormSelect>
  </div>
  <div className="mb-3">
    <CFormInput
      type="file"
      id="validationTextarea"
      feedbackInvalid="Example invalid form file feedback"
      aria-label="file example"
      required
    />
  </div>
  <div className="mb-3">
    <CButton type="submit" color="primary" disabled>
      Submit form
    </CButton>
  </div>
</CForm>

Tooltips#

If your form layout allows it, you can swap the text for the tooltip 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.

const [validated, setValidated] = useState(false)
const handleSubmit = (event) => {
  const form = event.currentTarget
  if (form.checkValidity() === false) {
    event.preventDefault()
    event.stopPropagation()
  }
  setValidated(true)
}
return (
 <CForm
  className="row g-3 needs-validation"
  noValidate
  validated={validated}
  onSubmit={handleSubmit}
>
  <CCol md={4} className="position-relative">
    <CFormInput
      type="text"
      defaultValue="Mark"
      feedbackValid="Looks good!"
      id="validationTooltip01"
      label="First name"
      required
      tooltipFeedback
    />
  </CCol>
  <CCol md={4} className="position-relative">
    <CFormInput
      type="text"
      defaultValue="Otto"
      feedbackValid="Looks good!"
      id="validationTooltip02"
      label="First name"
      required
      tooltipFeedback
    />
  </CCol>
  <CCol md={4} className="position-relative">
    <CFormLabel htmlFor="validationTooltipUsername">Username</CFormLabel>
    <CInputGroup className="has-validation">
      <CInputGroupText id="inputGroupPrepend">@</CInputGroupText>
      <CFormInput
        type="text"
        aria-describedby="inputGroupPrependFeedback"
        feedbackInvalid="Please choose a username."
        id="validationTooltipUsername"
        required
        tooltipFeedback
      />
    </CInputGroup>
  </CCol>
  <CCol md={6} className="position-relative">
    <CFormInput
      type="text"
      aria-describedby="validationTooltip03Feedback"
      feedbackInvalid="Please provide a valid city."
      id="validationTooltip03"
      label="City"
      required
      tooltipFeedback
    />
  </CCol>
  <CCol md={3} className="position-relative">
    <CFormSelect
      aria-describedby="validationTooltip04Feedback"
      feedbackInvalid="Please select a valid state."
      id="validationTooltip04"
      label="State"
      required
      tooltipFeedback
    >
      <option selected="" disabled="" value="">
        Choose...
      </option>
      <option>...</option>
    </CFormSelect>
  </CCol>
  <CCol md={3} className="position-relative">
    <CFormInput
      type="text"
      aria-describedby="validationTooltip05Feedback"
      feedbackInvalid="Please provide a valid zip."
      id="validationTooltip05"
      label="Zip"
      required
      tooltipFeedback
    />
  </CCol>
  <CCol xs={12} className="position-relative">
    <CButton color="primary" type="submit">
      Submit form
    </CButton>
  </CCol>
</CForm>
)

Customizing#

CSS variables#

CoreUI for React components use local CSS variables for validation for enhanced real-time customization. Values for the CSS variables are set via Sass, so Sass customization is still supported, too.

--cui-form-valid-color: #{$form-valid-color};
--cui-form-valid-border-color: #{$form-valid-border-color};
--cui-form-invalid-color: #{$form-invalid-color};
--cui-form-invalid-border-color: #{$form-invalid-border-color};

These variables are also color mode adaptive, meaning they change color while in dark mode.

SASS variables#

$form-feedback-margin-top:          $form-text-margin-top !default;
$form-feedback-font-size:           $form-text-font-size !default;
$form-feedback-font-style:          $form-text-font-style !default;
$form-feedback-valid-color:         $success !default;
$form-feedback-invalid-color:       $danger !default;

$form-feedback-icon-valid-color:    $form-feedback-valid-color !default;
$form-feedback-icon-valid:          url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'><path fill='#{$form-feedback-icon-valid-color}' d='M2.3 6.73.6 4.53c-.4-1.04.46-1.4 1.1-.8l1.1 1.4 3.4-3.8c.6-.63 1.6-.27 1.2.7l-4 4.6c-.43.5-.8.4-1.1.1z'/></svg>") !default;
$form-feedback-icon-invalid-color:  $form-feedback-invalid-color !default;
$form-feedback-icon-invalid:        url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12' width='12' height='12' fill='none' stroke='#{$form-feedback-icon-invalid-color}'><circle cx='6' cy='6' r='4.5'/><path stroke-linejoin='round' d='M5.8 3.6h.4L6 6.5z'/><circle cx='6' cy='8.2' r='.6' fill='#{$form-feedback-icon-invalid-color}' stroke='none'/></svg>") !default;

$form-valid-color:                  $form-feedback-valid-color !default;
$form-valid-border-color:           $form-feedback-valid-color !default;
$form-invalid-color:                $form-feedback-invalid-color !default;
$form-invalid-border-color:         $form-feedback-invalid-color !default;

$form-valid-color-dark:             $green-300 !default;
$form-valid-border-color-dark:      $green-300 !default;
$form-invalid-color-dark:           $red-300 !default;
$form-invalid-border-color-dark:    $red-300 !default;

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