Dear Jhilakshi,

Hope you are doing well.

Yes you are right. On loading this URL (http://m.imdb.com/feature/bornondate) the details of the celebrities is loaded through javascript. 

This is the reason that using urllib2 you are only getting the source before the java-script is called. 
 
Here you need to use selenium packages to load the entire page first and then grap the source code. 
 
Below are the things that you need to do:
 
1) Install selenium package
 
2) Import the package in your code like below:
from selenium import webdriver
3) Now use this package to load the URL and fetch the source code like below (You need to have firefox installed):
browser = webdriver.Firefox()
browser.get('http://m.imdb.com/feature/bornondate')
source = browser.page_source

4) Now you will all the details are fetched in source. You can now parse it to get the details.