server-side-validation

I've a JS dynamic form, where i can add or remove fields: Field 1 Field 2 Field 3 Field 4 Now if I remove Field 2 and add a new field: Field 1 Field 3 Field 4 Field 5 I'm sending this through Ajax POST inside a form element. My problem is server side PHP processing. How can I know how many fields I have inside $_POST array and what are their ids? I'm generating unique id using "field" + counterIndex, but following the example how can I be able to understand that I have a total of 4 fields and that number 2 is missing? By the way, inside the form I have static fields too. This can be done

I have an application who use ASP.NET MVC and KnockoutJS for the MVVM part. The server bind the data to the server by JSON. The client treat data and make a standard POST callback after that. I have now to handle some business logic like : The property1 must be superior to 10 if property2 == "FOOBAR" The property2 must be != "" Etc etc... (there is a lot of conditions I have to handle) So, to make things simpler, is it possible to avoid code duplicate between the server side code (C#) and the client side (JS) ? The idea would be to define the validation rules at one place (using Data

i'm currently integrating Google Play in-app billing to my androidgame project, i have a Node.js server set up and plan to send it the "originalJson" and "signature" value of the Google Play purchase response for server side verification. then i put up a bit of test on my Node.js server, first here are the "originalJson" and "signature" value of one of my purchase(fetched from the client side): originalJson:{"orderId":"GPA.1312-8694-0319-25069","packageName":"com.shihu.sm.testin","productId":"com.shihu.sm.testin.diamond","purchaseTime":1452598011176,"purchaseState":0,"developerPayload":"{\

Is it better to validate user input before it's sent to the server with JS or server side with PHP? Or maybe it's worth doing both just to be on the safe side? I'm creating a site (very simple at the moment) that has a members area/admin area/etc. At the moment i only have user input of Username and Password, in the future there will be more (email, address, etc), but whats the best practice of checking the data? Do i throw a load of 'if...else' statements at it until the user gets it right? Or maybe have separate variables for each value entered by the user and set it to true or false if it's

Of course, I know that server-side validation is a MUST . I'm using jQuery to validate form inputs and using jquery ajax to do server-side(PHP) validation at the same time. So I guess it may be safe since it's validating for both sides while javascript is enabled . Well, here is my problem... But what if the user has javascript disabled on his browser and if some bad guys try to do something bad from editing my client-side script? Because i'm making server-side validation through jquery ajax, and i'm planning not to validate them directly in php script(action="some.php") even user's javascript

I'm getting 2 kinds of receipt formats from Apple when i try to verify purchases on the server. Any idea what's the difference ? 1) content: { status: 0, receipt: { item_id: "662554154", original_purchase_date: "2012-10-12 08:32:12 Etc/GMT", purchase_date_pst: "2012-10-12 01:32:12 America/Los_Angeles", purchase_date: "2012-10-12 08:32:12 Etc/GMT", product_id: "com.example.mygame.tool1", bid: "com.example.mygame", version_external_identifier: "5647854", bvrs: "1.0", quantity: "1", transaction_id: "8844567822225544", app_item_id: "659563252", original_purchase_date_ms: "1350030732000", original