Question: On my new Ubuntu system, I've managed to get Apache2 up and running for developing my ZendFramework Web Applications...

I've got my `available-sites` config working correctly because I am able to request `localhost` and it servers up the correct `index.html` from my specified directory. 

**Problem :** if I request `index.php`, firefox attempts to download the file instead of running the script.

Any Ideas why this would happen? 

I've added the following to `httpd.conf` but it hasn't helped. 

```
AddHandler application/x-httpd-php .php5 .php4 .php .php3 .php2 .phtml

AddType application/x-httpd-php .php5 .php4 .php .php3 .php2 .phtml

```

Answer: 
You need to enable the PHP extension. Do this with the command `sudo a2enmod php`.
I have installed php 7.0 and getting the dailog box. I have installed apache php module for 7.0 version and it fix my problem.

sudo apt-get install libapache2-mod-php7.0