Don’t leave it to the auto-generated default messages.Explain to your user what is wrong and suggest solutions.
The beauty of these elements is that you can use them now: for browsers that don't support a particular input type, there is automatic fallback to standard textfields.
There are two keys to understanding why the automatic fallback works consistently in all major browsers: (unless "foo" is a recognized input type or "bar" is a recognized attribute of the input element).
For each of the new input types, we present a high-level description, an overview of the syntax, a description of the main attributes, a summary of which current browsers support it, and an example you can experiment with in your browser.
Using a library to do form validation can save lots of your development time. j Query Form validation library is the most popular validation library.
This post collects all my notes and references on j Query Form validation library.