You could try:
<?php
if ( ! empty ( $_SERVER['HTTP_REFERER'] ) )
{
?>
<a href="https://wordpress.stackexchange.com/questions/17750/<?php echo esc_url( $_SERVER["HTTP_REFERER']; ) ?>">Go Back</a>
<?php
}
You could try:
<?php
if ( ! empty ( $_SERVER['HTTP_REFERER'] ) )
{
?>
<a href="https://wordpress.stackexchange.com/questions/17750/<?php echo esc_url( $_SERVER["HTTP_REFERER']; ) ?>">Go Back</a>
<?php
}