special character validation on form submit

Hi @vjdoon,

Hope this message finds you well.

<?php
add_filter(
	'forminator_custom_form_submit_errors',
	function( $submit_errors, $form_id, $field_data_array ) {               
		$field_name = 'name-1'; //change the field name here
		$submitted_fields = wp_list_pluck( $field_data_array, 'value', 'name' );

		if( !preg_match( '/^[a-z]+$/i', $submitted_fields[ $field_name ] ) ) {
			$submit_errors[][ $field_name ] = __( 'There is something wrong ' );
		}

		return $submit_errors;
	},
	10, 
	3
);

This is a mu-plugin that will allow only alphabet characters, not numbers or special chars. You will find a guide about how to install a mu-plugin on this link.

Let us know if you require additional assistance.

Best regards,
Laura