In Firefox, go to “Options” under the “Tools” menu. Find your way to the “Content” section in the Options. Next to the “Enable Javascript” option you will see an Advanced button. Click on that and in the dialog that pops up uncheck the Move or resize existing windows option.

Once you save all your changes, Firefox will not be bothered by those nasty window resize scripts. There is also a more involved method of configuring the same option by using about:config, but I won’t get into that since the above method is much easier to do and follow.