Conditional Validation

In real-world applications, fields are often only required based on the state of other fields. Ctrovalidate handles this elegantly through the data-ctrovalidate-if attribute.

🧠 The Logic

The if attribute follows a simple controller-condition pattern: data-ctrovalidate-if="controllerName:condition"

• controllerName: The name attribute of the field to watch.
• condition: The state to check for.

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🛠️ Supported Conditions

:checked

Validation runs only if the target checkbox or radio is checked.

<input type="checkbox" name="newsletter" id="news" />
<label for="news">Subscribe?</label>

<!-- Email is only validated if 'newsletter' is checked -->
<input
  name="email"
  data-ctrovalidate-rules="required|email"
  data-ctrovalidate-if="newsletter:checked"
/>

:present

Validation runs if the target field has any non-empty value.

<input name="coupon_code" placeholder="Have a code?" />

<!-- Discount info required only if coupon is entered -->
<input
  name="referral"
  data-ctrovalidate-rules="required"
  data-ctrovalidate-if="coupon_code:present"
/>

:value=...

Validation runs only if the target field exactly matches the specified value.

<select name="contact_method">
  <option value="email">Email</option>
  <option value="phone">Phone</option>
</select>

<!-- Phone rules only apply if 'phone' is selected -->
<input
  name="mobile"
  data-ctrovalidate-rules="required|phone"
  data-ctrovalidate-if="contact_method:value=phone"
/>

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⚡ Real-Time Reactivity

Because Ctrovalidate uses a centralized RuleEngine, it automatically detects when a "controller" field changes and updates the validation state of all dependent fields instantly.

IMPORTANT

When a condition is not met, the field is considered valid and any existing error messages are automatically cleared.

Next Steps

• Built-in Rules — See all rules you can apply conditionally.
• SPAs & Dynamic Fields — Learn how to handle fields added after page load.