D For A Web Developer

[Nick Sabalausky via Digitalmars-d]

On Thursday, 1 May 2014 at 13:33:50 UTC, Marc Schütz wrote:
>
> IMO the client shouldn't do any validation, unless you can 
> really, really trust it. That's why I like to do things the 
> following way:
>
> 1. user input on the client
> 2. post using ajax
> 3. server validates and stores the data
> 4a. if transaction or data is invalid fails, send errors to the 
> client
> 4b. if everything's ok, tell the client to redirect to the next 
> page
> 5. on the client, add error CSS classes to the relevant fields, 
> or execute the redirect
>

That's a lot of unnecessary back and forth to the server for a
JS-based design. Plus it avoids some of the nicer UX enhancements
JS can enable, like validate-as-you-type, and does so without the
benefit of not requiring JS. Kind of a worst of both worlds (no
offence).

Naturally, the server needs to do validation no matter what. But
there's nothing wrong with doing an optional preliminary
validation on the client side first.