What is the difference between Run as php script and php web page in eclipse? -

I'm a newbie for php and am trying to use PDT for my php work. I have found that there are two options which I can use for Eclipse PDT for a php page

  Run as PHP script and run as php web page  < / Pre> 
 But wondering what is the exact difference between them. 
 
 In addition to this, I want to know whether the inter-eclipse is unique or is a feature of PHP. 
 

I will make a wild guess here, run as the script runs from PHP console ie CLI and run because the web Page is very self explanatory