Form creation: input widgets, data binding, and data validation - HTML5 in Action - page 89

Step 3: Build constraint fallback validation for IE9
You need to solve one last issue. If you try to submit the form in IE9, you'll see error
messages if any input fields don't pass the custom validation tests you wrote earlier. This
is great, but IE9 doesn't support the standard attribute-based validation parameters or the
email input type. To fix this, you need to create a function to scan the form for the input
field attributes required and pattern and input type email . When the app has col-
lected those fields, you'll test their validity. Add the code from the next listing to app.js,
directly after the code from the previous listing.
Listing 2.15. app.js—Fallback validation in IE9