Remote form should respect HTML constraints

[hyunbinseo]

Describe the bug

When submitting this form:

<form {...validateCode}>
  <input
    {...validateCode.fields.code.as('text')}
    required
    minlength={6}
    maxlength={6}
  />
</form>

1. required is respected - shows browser tooltip, and POST request is not made
2. minlength and maxlength are not respected. Entering 1 still results in POST request

Reproduction

• https://github.com/hyunbinseo/svelte-kit-template/tree/mre-kit-15270
• hyunbinseo/svelte-kit-template@7889aae

System Info

System:
  OS: Windows 11 10.0.26200
  CPU: (8) x64 Intel(R) Core(TM) Ultra 7 258V
  Memory: 3.86 GB / 31.48 GB
Binaries:
  Node: 24.13.0 - C:\Users\hyunb\AppData\Local\fnm_multishells\30476_1770345708960\node.EXE
  Yarn: 1.22.22 - C:\Users\hyunb\AppData\Local\fnm_multishells\30476_1770345708960\yarn.CMD
  npm: 11.6.2 - C:\Users\hyunb\AppData\Local\fnm_multishells\30476_1770345708960\npm.CMD
  pnpm: 10.28.2 - C:\Users\hyunb\AppData\Local\fnm_multishells\30476_1770345708960\pnpm.CMD
  Deno: 2.4.0 - C:\Users\hyunb\.deno\bin\deno.EXE
Browsers:
  Chrome: 144.0.7559.110
  Edge: Chromium (140.0.3485.54)
  Firefox: 147.0.2 - C:\Program Files\Mozilla Firefox\firefox.exe
npmPackages:
  @sveltejs/adapter-node: ^5.5.2 => 5.5.2
  @sveltejs/kit: ^2.50.2 => 2.50.2
  @sveltejs/vite-plugin-svelte: ^6.2.4 => 6.2.4
  svelte: ^5.49.2 => 5.49.2
  vite: ^7.3.1 => 7.3.1

Severity

serious, but I can work around it

Additional Information

No response

[hyunbinseo]

It would be nice if this was applied for programmatic validations as well.

If the form remote function has access to individual fields, it can call checkValidity for dirty input elements as well.

<form
  {...sendCode.preflight(PublicSendCodeSchema)}
  onchange={() => sendCode.validate({ preflightOnly: true })}
></form>