I have taken the backup of my website, that the developer has made in PHP, but, I am not able to understand, why it is not opening at my end, but, is running very well at the server.

PHP is a server-side scripting language which allows you to create dynamic web pages by putting script code inside your HTML pages. The code is executed by the web server before the page is returned to the browser. At your end there is web server loaded. that is why you are not able to view the view at your end.