<?php
add_action('wp_ajax_validate_email', 'validate_email_input');
add_action('wp_ajax_nopriv_validate_email', 'validate_email_input');
add_action( 'wp_footer', 'add_scrpt_to_validate_email' );

function validate_email_input() {
    global $wpdb;
    $email = $_POST['billing_email'];
    if ( email_exists($email) ) {
		echo "<p>";
		echo __("Your email is already registered. Please login", "groomi");
		echo "<a href='#' class='email_check_login_popup'>";
		echo __(" here", "groomi");
		echo "</a>";
		echo "</p>";
	}
    wp_die();
}

function add_scrpt_to_validate_email() {
?>
<script>
jQuery(document).ready(function ($) {
	$('input[name=billing_email]').change(function () {

		var input_value = $(this).val();
		var input_el = $(this).parent();

		$.post("<?php echo admin_url( 'admin-ajax.php' ); ?>", { action: 'validate_email', billing_email: input_value }, function (data) {
			$message = input_el.find(".message");
			
			if (!$message.length){
				input_el.append('<div class="message"></div>');
				$message = input_el.find(".message");
			}
			
			$message.append(data);
		});
	});
});
</script>
<?php
}