To uncheck check box after someone hits back button

I have a web based project in which I have used checkboxes

(number of checkboxes is chosen at runtime). When a user selects 1 or more checkboxes and press submit and then press back button, it does not show all the checkboxes as unchecked. Can anybody tell me how to make all the checkboxes unchecked on pressing back button

[337 byte] By [DevendraSobhania] at [2007-11-26 18:16:48]