Thanks swaroop it solved my problem.
I am trying this way only.however I missed the fullscreen=yes parameter.
by the way I have a simple url which I am passing in window.open() method. I dont have any target html page. In that case How should I use the below code.
var WShell = new ActiveXObject("Wscript.shell");
WShell.SendKeys("{F11}");
Thanks , Eshwar.