checkbox - FORM fields checking -

I have a simple form with many checkboxes. Now I need to stop users to proceed from this form if More than 3 checkboxes are selected. How should this be done?

Do prevent users from proceeding in fashion?

In general, just keep track of the number of check boxes in your checkbox check methods. In each check method, check your checkbox count variable and you can proceed from there to how you want the user to interact with your form.