changing file extention to PHP

[phppup]

I have a form that was written and works well as an HTML file.  Now I've learned a little (tip of the iceberg, i'm sure) and want to place password protection BEFORE it.  To the best of my knowledge, this will require SESSIONS and turning my form into a PHP file.  (I assume LOTS of reading is ahead of me... LOL)

 

Can I simply change the extension to a PHP, add the <? tags > and just keep the HTML in place?

Or do I need to make it PHP and ECHO every line of code?

Or is there another way?

 

And while on the subject, does a PHP file require anything before publishing, the way an HTML requires the

<!DOCTYPE> information?

[blacknight]

put <?php YOURAUTHCODEHERE ?>

and html stays this waya php file will print html properly as long as it is not inclosed in code tags

so your auth code can go in the top and stop the page load if the requirements are not meet

[batwimp]

The file needs to be on a web server that is running a PHP server, or the code won't work at all.

[scootstah]

You can mix PHP into HTML by either echoing HTML or putting HTML outside of the PHP tags. You can also use more than one set of PHP tags, and use PHP tags anywhere inside of HTML (including attributes and such).