Question: I am new to PHP, just downloaded it, and wrote a ["Hello, World!"](https://en.wikipedia.org/wiki/%22Hello,_World!%22_program) program:

```
<html>
    <body>

    <?php
        $fileName = "test.jpg";
        $txt = "Hello, World!";
        echo $txt;
    ?>

    </body>
</html>

```

But it doesn't work. I named the file `test.php` and opened it with Firefox and nothing was displayed.

Answer: 
You need to have a webserver that you open it through. Simply entering file:///whatever.php does not work, because the file is not parsed by PHP then. 

There are several web servers you can chose from, but my advice is [Apache](http://httpd.apache.org/), the worlds most popular webserver. I have it running on my Windows XP laptop along with PHP, and it's easy to install and setup, and works great. There are lots of modules that can be installed later if you need them. It's also free, not only as in free beer, but also as in open source.
If you have [command-line PHP](http://us3.php.net/manual/en/features.commandline.php) installed, you should be able to enter:

```
php test.php

```

to invoke PHP to run your program and display the output on the console.