But the great thing about them is that they all degrade gracefully.
So if an older browser doesn't support them, the fact that they're in the HTML won't 'break' anything, they’ll just be rendered as an NB While client-side form validation is great for enhancing user experience—fast, instant feedback to the user without making a round trip to the server—you will still need to validate any data submitted on the server, too.
Today I’m going to walk you through validating a simple booking form by using the Constraint API, and keep an eye on how you can make sure your forms stay accessible too.
To recap—or in case you haven’t read Sandeep’s article—with the dawn of HTML5, a raft of new input types and attributes were added to tags that allow the browsers themselves to perform the client-side validation for us: no Java Script required.
After making all these changes our HTML now looks like this: https://jsfiddle.net/ianoxley/9C2JD/ The good news is that HTML form validation is supported by all the latest desktop browsers, and most mobile browsers.So, what can you do if you have to support browsers that don't have support for form validation yet?One option is to not do anything and rely on your server-side validation only.This validation descriptor is valid only for drop down lists.The drop down select list boxes usually will have one item saying ‘Select One’ (and that item will be selected by default).In other words, in order to validate a field, you just associate a set of validation descriptors for each input field in the form. For such cases, a function is included which clears all validations in the validator object. Note that this validation if for fields like Textbox and multi-line text box.