framework/validators/RequiredValidator.php
public function getClientOptions($model, $attribute)
    {
        $options = [];
        if ($this->requiredValue !== null) {
            $options['message'] = $this->formatMessage($this->message, [
                'requiredValue' => $this->requiredValue,
            ]);
            $options['requiredValue'] = $this->requiredValue;
        } else {
            $options['message'] = $this->message;
        }
        if ($this->strict) {
            $options['strict'] = 1;
        }

        $options['message'] = $this->formatMessage($options['message'], [
            'attribute' => $model->getAttributeLabel($attribute),
        ]);

        return $options;
    }
public function getClientOptions($model, $attribute)
    {
        $options = [];
        if ($this->requiredValue !== null) {
            $options['message'] = $this->formatMessage($this->message, [
                'requiredValue' => $this->requiredValue,
            ]);
            $options['requiredValue'] = $this->requiredValue;
        } else {
            $options['message'] = $this->message;
        }
        if ($this->strict) {
            $options['strict'] = 1;
        }

        $options['message'] = $this->formatMessage($options['message'], [
            'attribute' => $model->getAttributeLabel($attribute),
        ]);

        return $options;
    }
{@inheritdoc}