My summary isn't clear... Currently, we have one error message when an input field suffers from being missing and another when it suffers from type mismatch. It would be nice to have one error message including both issues. For example: <input type='email' required> If the element has no value, it should show something like: "Please fill out this form with a valid email address.". This bug might need to revert bug 623870 because ideally, the error message could be kept as long as the element is invalid. This bug can also be WONTFIX if the solution in bug 623870 seems better in a UX point of view. Whatever the choice is, it's going to be after Firefox 4.0 release.