set jwplayer file src dynamically

Hi , I m using JW player 7.7.4. I need to change the file attribute value dynamically on java script click. How can we achieve this ? Please help. I tried doing this on click event : 1. jwplayer('playerid').file="video.mp4"; 2. jwplayer('playerid').load("video.mp4"); Both did not work for me. Thanks in advanced.