How can we validate individual form field In Magento 2?

Question

In Magento 1.x we can validate individual form field like.

<input class="input-text required-entry" id="name" title="First Name" type="text" name="name" value="" onblur="validate(this)"/>

function validate(id){
   Validation.validate(id);
}

In Magento 2.x How can we validate individual form field?

I want to validate only one field from multiple fields in a single form.

Answer 1

You can validate specific field using below code of line.

<script>
require([
  'jquery',
  'mage/mage',
], function($){
   $( "#new-button" ).click(function() {        
       $('input[name="field_mobile"]').validation();
       if(!$('input[name="field_mobile"]').validation('isValid')){
           return false;
       }
   });
});
</script>

NOTE: make sure you have added data-mage-init='{"validation":{}} in form tag.

Answer 2

I found this one to work:

$.validator.validateSingleElement('#input-id');

More about how it's implemented and used here: https://mage2.pro/t/topic/5504

Answer 3

<form class="form"
      action="<?php Your Action ?>"
      id="form"
      name="form"
      method="post"
      data-hasrequired="<?php /* @escapeNotVerified */ echo __('* Required Fields') ?>"
      data-mage-init='{"validation":{}}'
      enctype="multipart/form-data" >
<input type="text" name="title" id="title" title="<?php /* @escapeNotVerified */ echo __('Title') ?>" class="input-text data-validate="{required:true}"  value=""  />
</form>