Hi Balaji,
This is a browser feature and is intended to protect the user, If you could turn it off, all those sites spamming users with dialogs would have a way to stop it.
So in short, no.
Okay -
If you are not satisfied with the above answer and you want to go ahead and disable, then also you have an option - this is CodeProject buddy ;-)
Steps to recreate:
alert('Alert1');
alert('Alert2');
Alert2 is displayed with that prevent this page from creating additional dialogs annoying checkbox
Now change the above code into
alert('Alert1');
setTimeout(function(){
alert('Alert2');
}, 1000);
Now you wont see that annoying message and its checkbox in the second consecutive alert
Note: Dont reduce the timeout value, if its with in 1sec then browser will automatically add that warning to the alert.
Hope this helps you a bit.
Regards,
RK