Yes the 3rd button from the right in the lower row that looks like this # is the insert code button.
It does this:
<?php $file="counterx.txt"; $handle=fopen($file, "r+"); $hits=fread($handle,filesize("$file")); $hits+=1; fclose($handle); echo "$hits"; $handle=fopen($file, "w"); fwrite($handle, $hits); fclose($handle); ?>