Joint Entrance Examination (Main) is the first stage of the Joint entrance Examination, for the engineering undergraduate admissions to the NITS and Centrally funded institutes. Following are the details of this examination:

Important dates:
JEE Main 2014 Application Form Commences: 15 Nov 2013
Online Application submission ends: 6 Jan 2014
Confirmation Page Last Date: Last Week of Dec 2013
JEE Main 2014 Admit Card: 12 March 2014
JEE Main 2014 Offline Exam (Paper 1&2): 6 Apr 2014
JEE Main 2014 Online Test: 9th, 11th , 12th and 19th Apr 2014 (Shift 1: 9.30am to 12.30pm, Shift 2: 2pm to 5pm)
JEE Main 2014 Result: 3 May 2014
JEE Main 2014 AIR Declaration: June First Week 2014
JEE Main 2014 Rank Card: June First Week 2014

As you can see that all dates are over, so you can not fill the application form for this session, you should wait till the next session start.