However, Web Kit is the only rendering engine that gives you any means of customizing the bubble.
Even though Safari supports the constraint validation API, as of this writing (version 6), Safari will not prevent submission of a form with constraint validation issues.
To the user Safari will behave no differently than a browser that doesn't support constraint validation at all.
Bottom Line: We need a means of running code whenever a field's validity might have changed.
Problem #3: Knowing when a user attempts to submit a form Why not use the form's event is not fired until after the browser has determined a form contains valid data given all of its specified constraints.
Because you can only customize the look of the bubbles in Web Kit, if you want a custom look across all supporting browsers your only option is to suppress the default bubble and implement your own.
The following will disable the default inline validation bubbles from all forms on a page.
However, consider a script that automatically fills in the passwords, or even a script that changes a constraint attribute such as .
This could absolutely affect the validity of the password fields, yet, there is no event to know that this has happened.
Yet, despite being available in the latest version of all major browsers, constraint validation is a topic largely relegated to presentations and demos.