Show form action

When you move your mouse over any part of a form, the URL that the form with be submitted to will be displayed in the status bar. This will help you determine if the form is being submitted being submitted over secure http or not. Additionally the add-on warns you if the form uses JavaScript. Often forms use JavaScript to validate the information before it's submitted to the server but sometimes the JS code causes the form to be submitted to a different URL.

Hovering over the sign in form shows the submit information in the status bar.