Spring - login page to have terms and condition page
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In my web application, I am using Spring MVC. I have the default login page that spring MVC uses. In my login page I need to have a checkbox. While logging in, the user must enable the checkbox and then click the 'LOGIN' button.  
If he doesn't check the 'checkbox' a pop-up window should be displayed(with some error message).

I would like to implement this using javascript.

Can anyone please tell how to implement this?