<HIDE>This text will never reach the requester. But...
<SHOW>This text will always reach the requester.
In PHP, you can HIDE text with the if statement.
<?php if(false) { ?>This text is hidden.<?php } ?>
<?php if(true) { ?>This text is shown. <?php } ?>
This text may or may not be displayed based on previous commands.
<SHOW>
This text is always displayed.
PHP uses a command block archetechture. A command block starts with open curly bracket '{' and ends with close curly bracket '}'. If you enter into a command block, all of the commands will be executed in the order they appear. PHP will display all text that is not in a command block. The text will be written in the order it appears. To make sure text is displayed, you must exit all command blocks. But you can't just put in a bunch of '}' because extra curly brackets are grounds for a script error.
<?php if($whatever) { ?>
This text is displayed based on the variable $whatever.
<?php } ?>
Since the if statement block has closed, this text is
displayed regardless of $whatever.