If i want to know in which either my website is developed in asp .net, php, joomla or any other programs. Please help me on this ASAP. Thanks in advance.
It's your website - ask the guy who built it for you use your ftp client and see what the names of the files are ... if it's index.asp or index.php you have that answer joomla is php but you'll be able to tell from the folder structure if it's Joomla - just download from the official joomla site and see if they match... or look for a license.txt or readme.txt file on the server How have you got yourself in this situation?
To addon to sarahks post: The wappalizer pluggin also shows many details about a website (used CMS, webserver, scriping languages etc.). It's pretty accurate.