Is HTML5-validation supported?

[pekspro]

In the documentation it says for the input tag helper:

Generates HTML5 validation attributes from data annotation attributes applied to model properties.

But if I have an property like this:

[Required]
[StringLength(10, MinimumLength = 5)]
[Display(Name = "Computer name")]
public string ComputerName { get; set; }

And then uses the input tag like this:

<input asp-for="ComputerName" class="form-control" />

It becomes generated like this:

<input class="form-control" type="text" data-val="true" 
data-val-length="The field Computer name must be a string with a minimum length of 5 and a maximum length of 10." 
data-val-length-max="10" data-val-length-min="5" 
data-val-required="The Computer name field is required." id="ComputerName" 
maxlength="10" name="ComputerName" value="">

There is no minlength and required attribute as expected. Also, the form tag is generated with the novalidate attribute which to my understanding disables HTML5 validation.

I’ve also tried to disable client-side validation. This removes the novalidate attribute on the form tag, but the minlength and required attribues is still missing.

To summary, is HTML5 validation supported as it mentioned in the documentation?

Issue 8573 is a bit related to this.

I’m asking only by curiosity :-)

[mkArtakMSFT]

This is not yet support.
We've moved this issue to the Backlog milestone. This means that it is not going to happen for the coming release. We will reassess the backlog following the current release and consider this item at that time. However, keep in mind that there are many other high priority features with which it will be competing for resources.

[XmlmXmlmX]

Wow, that's really hard to believe. Open for 2 years.

[RihanArfan]

The dependence on a jQuery library for client validation in 2022 is quite concerning mainly as it's very legacy, performance, accessibility, etc. Vanilla JavaScript itself has come a long way and even GOV.UK have scrapped jQuery fully for native JS. Regardless, validation can be done fully without JS nicely.

All modern browsers have built in HTML5 validation which is really simple to use and works natively. https://developer.mozilla.org/en-US/docs/Learn/Forms/Form_validation

It's just a matter of switching the tags that are added to forms inputs (asp-for) to the HTML5 replacements. Stuff like data-val-required to required and data-val-length-min to minlength.

Some HTML5 attributes like maxlength are already added. ([StringLength(30, MinimumLength = 3)])

Internet explorer is EOL and not something that has to be considered anymore.

I don't think this would be a difficult thing to do and it'd modernise .NET Core a lot.

[javiercn]

We are going to use #8573 to track work in this area.

As for HTML5 validation specifically, we do not think it is a good fit as we identified some gaps compared to the current experience the last time we evaluated it.

[denschub]

@javiercn what are those "gaps"? From a browser developer's standpoint, I'd be interested in learning about those.

[javiercn]

@denschub I would need to dig into the details (we had this discussion many months ago and the developer on point is no longer part of the team), but I believe some of them were:

• Different UIs across browsers.
• Customizing the UI
• Custom error messages
• Error summary
• Async validation

Some of these might be possible (even though at the expense of writing code), but in general html5 validation works very differently from our current validation system and we would like to maintain backwards compatibility where possible.

[denschub]

Understood, yeah. There's probably some things you can already do with native APIs. For example, an Error summary could be built by iterating over form elements and reading HTMLObjectElement.validationMessage. Custom error messages can be set via HTMLObjectElement.setCustomValidity, etc. But I assume there's still a lot of things not possible, so feel free to file an issue in the HTML spec if you have any specific feature request!

None of that won't help with full backwards compatibility, of course. I was just curios, so thanks for the feedback!